Only thing I can remember finding was some porn above a cu that the Mrs was not happy about, and some stashed booty (camcorder) in a pub loft, the landlady said her brother had been up there and even said it was probably stolen.
I know and very difficult to judge without the full picture so to speak, but not a good means of access through a window. Again common sense needs to play a bigger part imo but balanced with risk and likely hood obv.
I would genuinely say from my experience, yes, certainly nowadays.
I think I would speak for all national and responsible co's when I say that's a big no-no, would you get paid if you fell or ssp, worth falling for a £200pa maint contract? ask your family see what they say.