A preliminary investigation (T326759) has found that the Campaigns extension may be affected by IP Masking.

Investigate whether or not checks are needed to ensure that only registered users are able to register for events, and temporary/IP users are NOT able to register for events. If needed, implement the checks.

This is spun out from T326872, in which we were told that the Campaigns Team do not own this. As an un-owned extension, Trust and Safety Product Team will take responsibility.