Invalid fair catch

[MD Longhorn]

I think you're asking for trouble making your ruling based on post-catch actions... if YOU thought it was a signal (or maybe more accurately, if you thought R's motions MIGHT be construed by K players as being a fair catch signal), then kill it. Sound like, however, you did NOT think it was a signal at all until AFTER the catch and you saw him not run. Err on the side of protecting him (and penalizing the poor signal)... but if you didn't consider it a signal - don't change your mind mid-play. You were right that you had a live ball... treat it as such.

(Besides, even though I'm an advocate of not whistling unless you HAVE to - a big loud whistle is appropriate on a fair catch... given that you did not whistle, players should play accordingly. This applies to both R and K.)