[JrJordan]

Actually an interesting river situation where it first doesn't seem to be. With the A and K both arriving, an argument could be made for check/folding if the passive player bets. Not a good argument, but an argument none the less if there is zero chance he could bluff when he senses weakness or bet a T. Since we don't want to check/fold in most cases, the choice is between check/call or bet/fold (we'll assume he's passive enough that we can't bet/call).

We're not going to induce a bluff very often from a passive, so it's a matter of deciding if the equity is higher from getting value from a lower pair that could check through (a 7 or T), or saving a bet when a hand we beat checks through (perhaps a rivered K or low kicker A).

I'm more inclined to believe he has a pair on the flop than he hit his case K on the river. Likewise, many legit A holdings might raise at some point, even if the player is passive. I'm more inclined to believe he has a 7 or T than an A, so I bet for value and plan on folding to a raise.