I am angered enough at the other two answers here to move my comments to an actual attempt at an answer. I think they really miss the point. In short:
This behavior from the big blind is illegal collusion and deserving of a penalty.
The intent of the BB here is obviously to signal to the SB that he is no threat in the hand. That's a big deal. This is a tournament right at the cash bubble, and this all-in from the short stack is a pivotal point in the game. Communicating like this at this time in the game is 100% collusion, and that should result in some kind of penalty from the hosts.
The BB and SB gain tremendously from this behavior if it's allowed.
When the short stack shoves all-in from the button, here are the possible outcomes (I'm assuming approximately equal SB and BB stacks, that they both cover the short stack by a reasonable margin, and that any reraise from SB or BB will be an all-in raise here. I'm also assuming a really low stack-to-pot ratio, since that's how these small tourneys work at the end.):
- Both SB and BB fold, and short stack gets the blinds, about a 50% increase to the all-in's stack here. Potentially also a reasonable hit to the SB and BB stacks.
- SB folds and BB calls.
- SB calls and BB folds.
- SB calls and BB and goes all-in. SB is faced with a stack decision and possible elimination.
- SB goes all in. BB is faced with a stack decision and possible elimination.
SB is next to act, so he's faced with a decision. He has two threats: the all-in short stack and the BB to his left. Even if he thinks he will fare well against the short stack, he must still fear the potential of a shove from the BB to his left. This is potentially a huge threat and may tip the scales toward outcome 1 or 2, and might also reduce the likelihood of outcome 5. Before the BB's comment, the lack of information protects the short stack somewhat. In fact, good short stacked tournament players will often rely on this very effect to enable more effective short stack play.
Now, let's inject BB's mouthy comment. What happens now? BB is saying effectively that he's choosing not to play this pot, and he wants to give SB information that will help him make the best decision about whether to try to eliminate the all-in. With this info, the SB now has no care in the world about the BB. He need not fear for his own stack. He can concentrate solely on the all-in's shoving range and his own cards and the stack sizes as if he's last to act. This will allow him to call with a wider range and attempt to eliminate the short stack. The short stack's shoving range is likely really wide here too, so calling with a more marginal hand might still be a good idea. The fact that the BB is no longer an issue is a huge deal.
- The BB benefits because he encourages the other two stacks to fight it out and he can win without playing.
- The SB benefits by having the benefit of virtual position in the hand and can therefore make a much easier decision.
- The all-in's sole advantage here of putting the SB in the position of fearing a potential shove from the BB is eliminated, leaving him unfairly at even greater risk in this pot.
My point is that this is not just some random jerk talking about his hand during the hand. This is a player trying to put the short stack at an unfair disadvantage by giving extremely valuable and inappropriate information to another player.
I can't find details about specific penalties that have been applied for collusion, and you don't really provide enough info that might point out mitigating circumstances (for example, if the SB had a huge stack and the BB just barely covered the all-in, he doesn't really pose the same existential threat to the SB as he otherwise might), so it's hard to tell how severe the penalty should be. The WSOP rules on collusion (#39-A and E, and #102) include topics like this, though they leave the penalties to the discretion of the tournament director.
All I can say is that I hope the BB at least bought you a beer after this.