What's the problem with the open practice? They've done it before. In fact, I'm pretty sure they have done it every year we made the playoffs. Actually, they might even have done it in 2015 before the last game since we were not getting anywhere near the playoffs. It's a good thing.
And the email announcing it did not, as some have said, necessarily presuppose the playoff game will be at home: "Check out your Boys in Blue prepare for the first round of playoffs at Yankee Stadium!"
This is clunky, ambiguous writing, but was also undoubtedly meant to indicate that you can watch them prepare at YS, not that the playoffs are at YS. Any other reading is deliberately obtuse to take offense.
How does the cliche go? Never ascribe to over-confidence and ignorance what can be blamed on an ambiguous prior grammatical reference. Or something like that.
Having the practice is fine, I think it's great. (And they did have one before the final game of the season vs. New England back in 2015). But the wording is so terrible.
"Check out your Boys in Blue prepare for the first round of playoffs at Yankee Stadium!" - Can be read as if the playoff match will be at Yankee Stadium.
"Check out your Boys in Blue at Yankee Stadium prepare for the first round of the playoffs." - Doesn't lead to ambiguity that we have NOT yet secured a home playoff game.