Nope, never. And my three Caminos are only a tiny fraction of my backpacking experience. The weight of a backpack should be on your hips. The back of my pack doesn’t even touch the part of my back where the bra hooks are.
Not unless you can jump up and down in your sleep sack.
That wouldn’t be my choice - or recommendation. It wouldn’t be very convenient to do every morning and night. The toilets aren’t always so close by, or vacant, or clean. I can remove and put on a bra with back hooks under my T-shirt while sitting in my bed. I took over the head ones on my first Camino, and they really did
not work for me. At all. YMMV.
Ha, well that’s up to you.
Seriously, not understanding this. My bras on the Camino dried in an hour out two on a clothesline in the sun. They were faster than my wool socks, but not quite as fast as my sports tech poly tshirts.