Bad Accounts

On a regular basis, we end up with a fair amount of bad/bogus accounts created as part of website activity.  I'm not referring to duplicates, but rather, junk accounts... Our standard practice is to inactivate them, but we're interested in mimizing or preventing this from happening going forward. 

Any advice or solutions you have found/implemented?

Thanks in advance.

Brian Seitz
Box Office Manager 
The Center for the Performing Arts, Carmel Indiana