Is it safe to climb the mast when the boat is ashore in a cradle?

[Chae_73]

He had done the same as the O.P...let a headsail halyard get hauled all the way aloft without a sail attached...

That wasn't my error on this occasion.

I was somewhat nervous about unfurling the 400sq ft genoa with the boat on the cradle, due to the fact that it was breezy and I didn't want to sail into the boat next door or generate other bad effects (such as putting a prop through the side of the hull, although I hadn't actually thought of that possibility at the time). So I wanted to get the sail down as quickly as possible. So I released the halyard from the spinlock. And then unfurled the sail. And then observed that the halyard was wrapped around the luff spar at the top of the sail. I thought we could maybe retrieve the situation by re-furling the sail, which did partially work but in all this messing about, the halyard managed to get a turn around something at the masthead, and stuck fast.

So that was that.