Umpires Don’t Make Law, Players Do.
Via Deadspin comes this great video of Joe Mauer, apparently reading the catcher’s signs and relaying them to batter Jason Kubel.
Putting aside Mauer’s denial, the interesting thing about this is whether it’s actually wrong to steal signs. There’s no rule against it, and so the answer is: it depends on the players’ perceptions of the situation. If you run afoul of the norm (i.e., a batter looking behind him) then you are likely to face informal sanctions in the form of a baseball to the body. Mauer’s sign-stealing, by contrast, seems acceptable: (1) it was a crucial game; and (2) the Tigers didn’t protect their signs despite knowing a man was on second. But it isn’t so acceptable that he can admit it publicly. That is: Mauer’s sign stealing was at once lawful, permitted in the social context, and publicly wrongful.
(H/T: Reader CDP. For more on the history of sign-stealing in baseball, check out The Echoing Green: The Untold Story of Bobby Thomson, Ralph Branca and the Shot Heard Round the World)