Folks,
Experience over the years tell me that it is OK if you are very careful.
I have been part of the crew several times, as somebody said, pragmatism.
It can have interesting consequences, old BOAC mate of mine did it at EGLL during an industrial dispute with tug drivers, a B707, ----- aircraft was blacked for quite a while.
We did it one night on the cargo ramp at (now) KJFK, again B707-320C. As S/O/SSCCSA (Secretary to the Steering Committee and Captain's Sexual Advisor), I was the one hanging out the back doors calling the directions, we were empty, fortunately.
We backed up a B747SP one night at YBBN, again an industrial dispute and the tug drivers refused to push, the aeroplane was blacked, didn't come back into Australia for something like a month.
Be extra careful if you are going to do it with a JT9 of any kind.
All good stuff, as long as you get it right.