Um, the admin is not really a "user" of the board... There is no legal implication that suggests that he cannot contact someone's ISP.... if they've violated a site's terms the admin of that site has every right to contact the violator's ISP and tell them they've misused the site.
When someone wrongly uses someone else's capital..... the "victim" can get justice, if there is proof.
We as administrators have to uphold that.... for example, would you let a burglar into your house and stand back while he steals everything? (assume he is unarmed, and you don't care)
Same thing.... if we let people that can't follow the rules here, they'll bring the forum down.... the most effective way is to tell their ISP.
btw.... for a while it was admin verification however that became a lot for us when there was a big registration boom. So we switched it to email verification.