I'm using 1.7.4 (just updated this am ) and we had one of our players create a new user, one that was a duplicate account, so I deleted it this morning rather than approving it (after sending them their correct login information/etc). When I checked the tables, the entry was removed from the "people" table, but there was still a user in the "user" table.
Also, for the record, in such cases I typically use the "merge backwards" option, which will keep the user's new user name, password, contact info, etc., but "move" it all to their pre-existing account, so that their old id number, waivers, registrations, team affiliations, etc. are all preserved.