What does it mean for a guy to be white boarded?
How does this happen?
Is it good or bad?

You probably mean whitelisted, which is a good thing. If you have treated a provider decently, she can put you on the white list here, which shows that she is vouching for you as a decent client. While some providers may do this without prompting, you generally will need to ask them. After you have some recent white listings showing on your profile here, it can make screening quick and easy with some providers.

but perhaps you're asking about something kinky or a fetish based on water boarding. If so I'll have to go with no idea how it happens and does not seem good at all but each to their own.

It is onemore reassurance that someone out there thought you were a great guy when you met and would continue to be so.  All prividers have there own standards about this.  Iprefer to have met several times...as men can pull off being wonderful once but it takes quality to remain so over and over.