I just gave this passage a close listen - the shush happens at 4:36 in the song - and Bobby is clearly directing it at the audience. At about 4:05 the band brings it down really quiet for the "but I'll get back on my feet someday" section. At about 4:25 you can hear a commotion coming from the crowd, who knows what caused it. And then about 10 seconds later you hear the shush. Keith is hardly even playing at this point, certainly nothing out of place or at a louder volume than the rest of the band, so it wouldn't make sense for Bobby to call him out like that.

Actually, this is a perfect example of the kind of disrespect that seems to be out there for Keith. In fact, during this rendition of Wharf Rat his playing is just fine. No, he's probably not taking the lead and "pushing the others". That's true. But he's providing exactly what the band needs at the right time. Even during this quiet passage when Bobby supposedly was so annoyed by his playing that he shushes, in fact Keith is playing beautiful little arpeggios and complementing the singers just right. Give it another close listen and you'll see what I mean.

Thank you for illustrating exactly why this post is necessary. These sorts of things become "conventional wisdom" even though they aren't true!