Unplanned movements do cause a little, but not insurmountable problem.
You will probably understand that towed movements and infrequent crossers were our only unplanned traffic. Initially towed traffic had to be notified in advance - like that's going to work! - but that quickly passed when we realised that we could input as they called.
Most inputs, being menu driven, were fairly easy to do especially if you have regular customers. Frequent unfamiliar callers do present more of a challenge, but there are units with such traffic who I'm sure will respond.....