It depends on the song, what solo is being played, and working out on the fly the best way to synchronise at the end. My guitarist will usually realise when he's made a mistake, I'll usually do a very obvious run into the next chord change (add/remove a bar - whichever way is the most musical), and things will then generally fall into place
Edit: Damn auto correct - I wouldn't want to remove a BAT - although I might appreciate being handed one!