..fourth and short deep in your own territory, 4 minutes left in the game.
The Bills didn't need to know a fake was coming, it's not even necessary to know it. The situation will dictate to any decent opposing ST coach that you're prepared for it for one simple reason...there's no other huge upside that the Bills needed or wanted from the play. The Bills are up late in the game, the Rams are punting from fairly deep in their own territory...the only thing the Bills want is to safely end up with possession of the football.
Are they going to go for a punt block formation? No, there's absolutely no benefit vs the risk.
Are they going to bail out in an attempt to set up great return? Probably not, they just want hands on the ball and work the ball down the field chewing up some clock.
A fake at another time during the game I'm okay with...not this one. The D had given up what 40-50 yards total in the 2nd half, this fake was unnecessary. If he wanted to go for it on fourth he might as well have left the offense in.
That my bite on the situation.