OpenID – trouble with double accounts being created

I permit registrations on my site, and a few people have tried logging in with their openID urls before properly setting it up in the openID section. instead of seeing if that url’s already used anywhere, openID is somehow created a new user account, which is obviously not what the people intended to do.

Is there any way for the openID plugin to check to see if the url the user is using is already in use?

What should I do about the users that now have multiple accounts? Just delete the openID one and try to attribute all the comments and posts to the correct author? eww..I have over 10,000 people on my site, I’d rather not have to do that manually ??