Not have a real-name policy. Identity is too complex a concept to be reduced to simple data structures, no matter how much us engineers desperately want to. If

Not have a real-name policy. Identity is too complex a concept to be reduced to simple data structures, no matter how much us engineers desperately want to. If one is concerned about impersonation, attack impersonation - impersonation can and will happen even with a strongly-enforced real-name policy (name changes, anyone?). Empower support to deal with impersonation on a case-by-case basis. Open-endedness in this sort of enforcement can be risky, but it's certainly better than the "baby with the water" policy the way it is right now.