Scamming is a virus, though many steps were taken they happen.
As above sniffdog said, A member with minimum no.of posts would be good.
Providing service to 3 trusted member is a bad idea. How they gonna test it. They move their site and test it with every host every month.

Prevention of scam:
1. Payment processes have resolution center. We can raise complaints over there to block their payment.
2.Always keep the invoices of the host as backup.
3.Take weekly site backups.
4.KWWH Mods must get their personal details and keep it confidential.
5.If there are any suspicious things happening on thread,Mod must give atleast 24hrs of time to hosting providers,before they make their details public.
6.Popularity and Trusted rating option must be added to forum, with which users can rate the host.