Originally Posted by TheWylders

What have you got your threshold set at? I had the same problem with aol users but changed the threshold a little higher and haven't had a problem since. If someone share's a password on a board or something it'll still get turned off pretty quickly, but allows several different ip's before blocking the account.
Also do you have a page set up to direct the members to after their password is locked explaining that aol changes the ip address and to contact you if their password is locked and they didn't share the password.
I keep a pretty close eye on my pennywize stats and tweak it as necessary, haven't had any problems or disgruntled customers in months.