[StellarWind]

Clearly you can cap if you want but calling is probably better:

1. Button may cap and then you get what you wanted without tipping your hand.

2. If Button just calls the initiative will remain with SB. Now you can decide about raising after you see the flop. Putting the extra bet in on the flop carries a much higher EV than preflop because you only do it when the flop is favorable. In essence this play saves a bet everytime the flop is some atrocity like AQ4 while giving you the same action as capping when the flop is good.

The bad LAG button is the key to making this work. I'm assuming that when he's confronted with two bets on the flop he'll pay first and think about his cards later. If Button caps you can checkraise the flop because he'll always bet. If Spammuel forgets to bet your flop after his 3-bet is called, you can still recover you bet by checkraising the Button. Another trick is to smoothcall Spammuel's flop bet when you hit your set and let the Button raise for you.

Of course if I'm not describing your actual button then my advice may not apply. But I hope that I've made my basic point. There is much more to this type of situation then computing your bet equity and capping anytime it looks positive.

PS: I should add that the jacks play an important role in this. This hand tends to be awesome or worthless depending on the flop. With a better pocket pair there will be fewer OMG flops and the option to get away from your hand cheaply is worth much less. Also if you like the flop it is unlikely that Spammuel will completely hate it. If you had KK and the flop came KQ7 there is a real chance he might walk away from a hand like 88 or A9s without betting. But if you like the flop he usually has a minimum of overcards or second pair and will probably bet.