The Yankees, it was reported yesterday, took exception to some whistling emanating from the Houston dugout during Game 1 of the ALCS. It was, they felt, an ongoing signal to hitters about either the type or location of the upcoming pitch. According to SNY, a Yankees coach—who didn’t come forward directly, but was outed to the network by three sources—called out the Astros about the practice during the game, leading to some back-and-forth yelling across the field.

“The whole dugout was pissed,” SNY’s Andy Martino quoted one of the sources as saying. “Everyone was chirping.”

On one hand, sign stealing is a long-accepted practice around the league, with the clear-cut caveat that it not be technologically aided. A runner relaying signs to the hitter from second base might be viewed by opponents as annoying, but his presence means mostly that the victimized team needs better signs.

Take the practice beyond the fences, however, and real issues arise. Never mind that spying on an opponent’s signals via a ballpark video camera is against the actual rules—it’s also seen as below-board chicanery by people who would otherwise harbor a soft spot for thievery of a more legitimate (ie: non-technically aided) persuasion.

Which is where things grow hazy about New York’s accusations. If the Astros were whistling from the dugout, it almost certainly means that they were getting their information from someplace else within Minute Maid Park. Unless New York catcher Gary Sanchez was dropping his fingers so far below his squat that his signs could be read from the sideline, folks in the Houston dugout would have no legitimate way to figure out what to signal and when.

There’s also the not-insignificant detail that the Astros were accused of this very thing just last season.

Then, a team employee named Kyle McLaughlin was stationed in a dugout-adjacent photographer well (without appropriate credentials, it should be noted) and caught aiming a cell phone into the dugouts of both Cleveland (Houston’s opponent in the ALDS) and Boston (during the ALCS). The Astros claimed that McLaughlin was placed there to insure that their opponents were not spying on them, using then-recent allegations of Apple Watch sign-stealing impropriety lodged against the Red Sox. (Why McLaughlin was snooping on Cleveland remains unclear.)

Last year, it wasn’t whistles that the Astros used to signal their hitters, but claps or audible whacks of a trash can. That info that came from the A’s and Dodgers, both of whom aired similar suspicions about Houston’s shenanigans, the latter during the World Series.

This is hardly the first time that a team has whistled signals to hitters. In The Baseball Codes, I recount an instance in which the Yankees, in a turn, did some whistling of their own. It happened during the late-1950s and early 1960s, and began with pitcher Bob Turley, an extremely proficient practitioner when it came to stealing signs. Turley was so good, in fact, that he was occasionally utilized as a first-base coach for that very purpose. From the book:

Turley’s relay system was simple—he’d whistle whenever a pitch was different from the last one. Hitters would start every at-bat looking for a curveball, and if a fastball was coming, so was Turley’s whistle. He’d then stay silent until something else was called. The pitcher was so good that when he went on the disabled list in 1961, manager Ralph Houk wouldn’t let him go home, instead keeping him with the team to decipher pitches. (Roger Maris, in fact, hit his sixty-first home run of 1961 on a pitch he knew was coming because third-base coach Frank Crosetti, doing his best Turley imitation after watching the pitcher for years, whistled in advance of a fastball.)

Eventually, people began to catch on. Among them was Detroit Tigers ace Jim Bunning, who grew increasingly angry as Turley whistled and the Yankees teed off during one of his starts. Finally, with Mickey Mantle at bat, Bunning turned to Turley in the first-base coach’s box and told him that another whistle would result in a potentially painful consequence for the hitter. Sure enough, Turley whistled on Bunning’s first pitch, a fast­ball at which Mantle declined to swing. With his second offering, Bun­ning knocked Mantle down. The on-deck hitter, Yogi Berra, could only watch in horror. When it was his turn to bat, Berra turned toward the mound, cupped his hands around his mouth, and shouted, “Jim, he’s whistling, but I ain’t listening.”

Positioning a sign thief in a coaching box is the primary non-technology-aided method the Astros might be able to employ if they are indeed stealing signs. It seems like a longshot, but, needless to say, nobody in that clubhouse is talking about it.

I collected more recent examples of illicit, beyond-the-field-of-play sign-stealing accusations from around the league for my post on the Red Sox smartwatch controversy:

The Blue Jays were accused repeatedly, by numerous opponents, of similar activity at the Rogers Centre, to the point that ESPN commissioned an expansive expose on the practice.

The Phillies drew the ire of multiple teams—including the Yankees, in the World Series—for their alleged ballpark shenanigans. It didn’t help that, in 2010, their bullpen coach was caught on the field with binoculars.

In 2014, Chris Sale accused Victor Martinez and the Tigers of having somebody in center field.

The Padres have had (probably baseless) accusations thrown their way, as have the Marlins.

Last year, MLB responded to the allegations from and about the Astros by sending an additional nine staffers—three from baseball ops and six from security—to monitor the next game, including placing somebody in each team’s video-review room. Ultimately they declared that Houston did nothing wrong.

This year, we’re getting more of the same. Suspicions about Houston’s use of surveillance technology in its home ballpark has continued unabated. “They are NASA,” said a major league coach in the SNY report. “If a pitcher is tipping and the players can see from the dugout, no biggie. If they get it from somewhere else, that’s dicey.”

Ultimately, all this subterfuge didn’t help the Astros. New York starter Masahiro Tanaka pitched six shutout innings, and the Yankees pounded Zack Greinke and four relievers in a 7-0 victory.

In Game 2, we saw New York starter James Paxton and catcher Gary Sanchez changing signs throughout the game, even with nobody on base, which is as clear a sign as one can get that a team is harboring some nasty suspicions.

This affair is just getting started. If the series makes it back to Houston and the Yankees suspect that the practice is still going on, expect some bloody hell to be raised.

In the meantime, the Nationals have a good long while to figure out how to handle the situation should the Astros advance. The spy game, it seems, is alive and well in baseball.

Update 10-18: According to Ken Rosenthal, baseball has cleared the Astros of wrongdoing.