Without slinging any mud.....
Certainly at EDI crews call for push (and start) routinely when they are not fully ready. I'm sure that they're under a great deal of pressure to acheive on-time departures, but it really is deeply unhelpful - particularly as we can't see a bloody thing from the tower and so have to rely one hundred percent on what crews tell us.
I cringe each time someone says "but he's still got a door open" when they're given a conditional pushback on the aircraft next them - do they have any idea how unprofessional the resulting "XXX 3HY are you really ready to push? Do you have a tug?" sounds on the frequency?
It's particularly annoying when four or five aircraft from the same company, all parked on adjacent stands, all with the same planned departure time, get into this routine, but it happens almost every day.
And that's really where the blame lies, for my money, with the aircraft operators. Can't blame the crews too much when the root cause is outwith their control. They don't want to loose their place in the queue, so they try to pre-empt. It should be the crews who complain to the companies for boxing them in to start with!