you can't host good TF2 server on C2750. It's cool only in ark.intel. On practice - nothing special.
Just get any e3 or may be dual old xeons - that's will be fine.
IMO, it's really impossible to verify foreign person. Even if he will send passport scan, because this scans costs around 10-20$.
And really, I dont care who are using my services, till it doesnt violate our ToS. Why should I think something bad about all my customers just because 0.1% of my...