Last night sitting on the ground heard a poor JMC driver trying to get off 20 minutes early, unrestricted slot not much traffic around midnight. Controller would not let them start stating only that schedule was 2350 and he would have to re-file if he was to go before that. what then happend could only be described as a bad joke, where for the next 15 minutes said driver was switched between ground and Palma operations without any progress or explanation until he was told that although he was unrestricted at 2350 he MIGHT be resricted if he went 20 minutes earlier. ???