The idea didn't appear to be to create a comprehensive list of all ball python breeders, but simply a list of all ball python breeders who are on this forum, and opt into it.
If you simply state that being listed doesn't imply an endorsement, and suggest to people that they should seek references and check into businesses before making any purchases, that should be sufficient to keep it low maintenance. There's no reason BP.net has to be responsible for background checks.
Once a year, dump the list and have people re-apply. If a breeder isn't interested in maintaining their own listing, there's no reason to list them. That would keep the list reasonably up to date.