As far as I'm concerned, final decison on accepting LMC's should rest with the dispatcher because they're responsible for the turn-round. Now with some airlines, pilots will accept LMC's (which delays the flight) and then asks for an on-time departure to be recorded. On the other hand, if the dispatcher accepts LMC's without telling the pilot, and delays the flight, the pilot insists on recording a delay. So if the dispatcher is responsible for driving the turn-round, the decison on LMC's is made by him/her. Some people would say that the LMC question shouldn't be an issue if check-in closure times were adhered to all the time.