Does it matter? Class D (or formerly GAAP) controllers give sequence and are not responsible for separation. That is purely a matter for the pilot(s) involved. Had a Citation right up my bum in a 172 on downwind the other day... how he stayed behind is beyond me but whatever, separation is not a matter for the controller. No-ones fault, just a stupid system, just asking for same to happen again, especially when everyone is inexperienced, busy or distracted....