We've had some issues with abuse of Special:EmailUser by users who've been blocked (in some cases, blocked way before the prevent-e-mail option was around). It would be very useful if use of Special:EmailUser left an IP footprint in the CheckUser database, if that's possible. I assume this would be a change to CU rather than MW itself, hence categorisation - apologies if wrong!
Version: unspecified
Severity: enhancement