[pzhon]

Here is some anaylsis:

The consensus is to call or reraise with TPTK or better or the nut flush draw. About half of the people responding would fold AQ. About 2/3 would fold the second nut flush draw.

Let's suppose you are in the big blind, and someone open-raises in middle position with AJ-AK, KQ, and 99-AA. After the A97 flop, there are 30 pocket pair possibilities, 36 Ax hands, and 16 KQ hands. Some of the KQ hands would not bet the flop, but most people indicated that they would bet on the flop with KQ or TT.

If you check-raise, you are risking 25 BB to win 16.5 BB. How frequently will you be rewarded with a fold?

AA: 0/3 hands will fold.
KK: roughly 5.5/6 will fold.
QQ: 5.5/6 will fold.
JJ: 5/5 will fold. Some would not bet the flop.
TT: 5/5 will fold.
99: 0/3 will fold.

AK: 2/12 will fold
AQ: 6/12 will fold
AJ: 10/12 will fold.

KQ: 9/10 will fold.

The total is that about 48/74 hands would fold after that sequence, 64%. That's greater than the 60% needed to fold to justify check-raising as a complete bluff.

That doesn't mean people are bluffing enough in practice to make it worth a call. Nor does it mean a random opponent will fold as much, or will bet so many hands that they are willing to fold to a check-raise. It is something to think about, as it shows an exploitable weakness. It suggests a semi-bluff would be quite profitable.