Remove destructive GET request from RSVP workflow

After some discussion, and some research into how other sites deal with carrying intentions through a login cycle I decided to remove the special case, destructive GET request for RSVPing to events. This simplifies the code and makes RSVPing to event work exactly like following groups.
I'm curious how Django behaves when we want to generate URLs for an event listing page. Would it execute a query for each event to retrieve the group slug?