I saw one "genuine beachgoer" who was carrying a beach towel and got into his car well after midnight, but maybe the towel was a clever decoy just in case cops asked him what he was doing there that late! The council should install sensor-activated boom gates on each car park so cars that are in before 9pm can still get out after lock-out (just like at Thorndon Park).
Tennyson was open for "business" well into the night on New Year's Day (still open at 2am). The council must be reluctant to chain up the carpark gates early on a hot summer's night as they wouldn't want to lock in the vehicles of any genuine beachgoers.