$50NL 6m Check behind here?

[Reid L]

Full Tilt Poker
No Limit Holdem Ring game
Blinds: $0.25/$0.50
5 players
Converter

Stack sizes:
Hero: $49.25
CO: $50
Button: $32.15
SB: $43.75
BB: $73.15

Pre-flop: (5 players) Hero is UTG with K[img]/images/graemlins/heart.gif[/img] A[img]/images/graemlins/heart.gif[/img]
<font color="#cc0000">Hero raises to $2.5</font>, 3 folds, BB calls.

Flop: Q[img]/images/graemlins/club.gif[/img] 9[img]/images/graemlins/club.gif[/img] A[img]/images/graemlins/diamond.gif[/img] ($5.25, 2 players)
BB checks, <font color="#cc0000">Hero bets $5.25</font>, BB calls.

Turn: 2[img]/images/graemlins/spade.gif[/img] ($15.75, 2 players)
BB checks, <font color="#cc0000">Hero bets $10</font>, BB calls.

River: A[img]/images/graemlins/club.gif[/img] ($35.75, 2 players)
BB checks, <font color="#cc0000">Hero bets $15</font>

I thought about checking behind here but decided to bet out. Should I have checked the river?

[CityLife]

I'd bet. Unlikely that BB is going to check the river if he made the flush, and you'll get called a lot of the time by a smaller ace. Maybe he filled up on the turn, but if so then he's played a set or two pair very passively.