Very few leagues have a 100% return rate at this time, and while I realize invites have only been out a few days, I am growing concerned (I live in a constant state of concern, so not really a surprise there). I can tell you the very few that have bounced back have been corrected, so people should have gotten an invite.
So if you see a guy in the tank (or you know he has been here and will be back with some regularity) that is in your league and has not yet claimed his team - give him a nudge! PM him, perhaps he is unaware, hasn't checked email, or did not get his invitation. I expect problems from lower leagues and new guys, but we are missing a few heavy hitters here. I will be re-sending invites, and I PM guys when I see them and go through leagues and look for absent owners to notify (unfortunately some are infrequent visiters to the tank and a PM is useless).
So help your commish out!