As the lens mount is well able to take the weight of the body, then provided there was no extra strain introduced in transporting, lens taking the weight of the body, then I would not have thought there would be a problem. If the conditions were to be dusty and I only intended to use a long lens then I would prefer not to attatch it in those conditions.
My 400 has a velvet type of blackout in the tube, rather than paint, so making it harder to cleanly expell dust with a blower.
Interesting thread all the same just in case I come across a steal on a 500/600 f4 AIS. A/F would require a lottery win.
Don