Checking It Down

OK, so here is the situation. We were playing Texas Holdem the other night at work (shhhh- don't tell). 9-person tournament that was down to 3 players. Button (Ac/Kh and very short stack) moves all-in. SB(Ad/8d) & BB(3s/5s) both call with about equal big stacks. Flop comes 7c 8c 9h. SB moves all-in. BB forced to fold. Turn is 6h. River is Kd. Anyone else see a problem with what the SB did? By the way, I was BB. Even the Button agreed that was a really bad move on the the SBs part. We just couldn't make him realize that was a terrible play. Anyway, here is an article I found at rgpfaq.com. Let's hear what you all have to say....

Thanks,
Ogre