That's a problem simply because it's not uniform. Go back to
@Fly_Unity's post and take it at face value. He gets a clearance out of Scottsdale late at night, an otherwise very busy airport below a Class B shelf. He takes of expeditiously and reports in.
Not a thing wrong with it. Except a very unhappy controller threatening to report a deviation. A controller who is probably in the category of those who would never issue a climb into their Class B airspace any time of day or night without specifying a departure window. Maybe, like
@NovemberEcho, finds it hard to believe its even legal and is convinced the rule is that in the absence void time language, you have not been released. Guaranteed, if there was a loss of separation, our pilot would have been given a hard time. Or, worse, metal touching metal.
This really isn't about what the "correct" interpretation is. IMO, this kind of operational inconsistency is just bad. I guess it would be OK if the .65 - and the AIM - were explicit but they are not. If it were explicit we wouldn't see controllers arguing about its validity. If it were explicit pilots other than those who have experienced it would know about it. How was NovemberEcho to know which type of control facility he was dealing with and whether or not to question the lack of the void time?