[D. Bosola]

Why? The flop is fairly innocuous and AA/KK have shown so much strength preflop they are unlikely to get any action when they bet. Checking behind on the flop may induce Kramer to bet out on the turn, at which point AA/KK can shove. The 5h on the turn puts a flush draw out but the odds of Kramer having two hearts are fairly remote, there AA/KK can afford to give yet another free card. Given how Kramer is under-repping his hand, AA/KK have to think he is folding to a turn bet, and checking behind twice just reeks of weakness, so it's very hard for any semi-aggressive player not to at least stab at the river with ATC here.

Anyway, I'm not saying AA/KK are likely here, just possible. JJ isn't the only hand that villain can have.