Well, I agree that charging for a service is a pretty good way to keep freeloading leechers out, but I don't agree using WoT would work for when someone wants to offer a thing for free but still don't want to get sybil-attacked or abused. WoT would solve it, but it's probably too restrictive for most cases in which people resort to the email/phone combination today -- I do think most of these cases are stupid.