I probably get up there as often as anyone, and have been doing it for a long time. Saturday will be my fifth ascent this summer—third with an overnight at Trail Camp. The gear I stash is always in plain sight and has never been bothered.
I leave my overnight gear laid out. The main reason: I never know when something might happen and I have to spend another night there. Throw the loose things inside my sleeping bag. Fold the bottom of sleeping bag/bivy sack/pad/ground cloth over to the top, and add a couple of rocks to keep wind problems at bay and deter the critters. Add my overnight pack. Put a rock on top of the pot and stove.
Many of us have heard you should leave zippers open on packs and tents: that marmots and squirrels are curious creatures and just want to snoop around. I don't necessarily believe that. It might be yet another one of those things that has no foundation in fact, but sounds sensible and so gets passed along as gospel from one person to another. I never unzip, and I've never had a problem.
So I'm not convinced that animals gnawing into closed packs and tents is at all common. It may happen, but it's never happened to me in a lot of climbs over the years. But you have to use your head. For example, I wouldn't dump a handful of nuts or a slab of bacon into an outside pocket.
Last summer, I was with a group. One of the others left his sleeping bag and bivy laid out and unzipped. Another left his tent unzipped. Something—marmots undoubtedly—got inside both and peed while we were gone, making quite a mess.