Is that so unreasonable? If I agree to forward someone's mail you would probably expect me to do some basic sanity checks in order to establish whether I am likely to be forwarding IRS documentation or anthrax. Why does the internet always get a pass on established societal norms?

Depends on if you're ok with the tradeoffs of KYC as they require comprehensive identity verification, and depending on service changes to structure to adhere to a per-person account model.