While I am flattered by Bulldog's compliment, I have to admit that my post in that other thread didn't actually address the issue at hand, i.e., the timing of a signal made by a ball carrier following a catch or recovery of a legally kicked ball. To be truthful, we don't have positive direction on this issue. I am with Jason in that, if it happens virtually immediately after completing the catch/recovery, this rule applies, i.e., the ball is dead, no advance is allowed, and he does not have fair catch protection.
In a case of a player completing a catch or recovery of a legally kicked ball, then taking a few steps before he encounters opponents, when he makes a signal, and gives up, I'd rule an invalid signal, the ball is dead, no advance is allowed, and he does not have fair catch protection.
In a case of a player completing a catch or recovery of a legally kicked ball, then advancing beyond the first 'wave' of opponents that he encounters, and then throws his hand up like a fair catch signal - whether he stops first, or continues to advance while signaling - I believe I would judge that his signal is nothing, the ball is alive, and he may be contacted in any legal manner.
If it ever actually happens, I'm sure we'll get a rule edit/change, or at least another AR.