As for what the maids do with stuff left in the room, I have a story.
Charter trip, upon departure everyone's luggage would be picked up from rooms, just inside the door, starting at 0900 to be taken to the airport.
Check out time was 11:00am.
We went to breakfast, played a few machines.
We had stowed in our room a plastic hotel logo bag containing items our friend had bought at one of the boutique stores.
I didn't place it with the luggage. Put it next to the bed against a wall.
About 10:15 went up to the room to use BR and check out per TV.
Funny, the room had been made up, as for a new guest.
Then I noticed, the bag with Connie's purchases, which I had set by a wall was GONE!
I started calling, got guest services, explained about the missing items, and BTW why the heck was the room cleaned and we hadn't even checked out yet?
Guest Services told me to stay in the room, someone would be bringing the bag up to our room. We waited, about 30 minutes.
Meanwhile I called Connie to let her know what was going on. She said SHE had also had some stuff taken from her room before she checked out, a shopping bag (from Harrah's) of about 12 bags of popcorn and some chocolate things she had bought for friends at one of their shops. She had bee-lined to the housekeeping room, caught up with a housekeeper/cart that had HER (Connie's) stuff on top of the cart, and a male housekeeping person already eating out of one of the bags of popcorn. They apologized and of course gave the rest of it back to her. I told Connie she MUST report this. She was going to let it go, but she did report it.
Anyway, a maid was cleaning the room across from ours and I asked her about our stuff. She pouted while denying knowing anything about it, then said "Security picked it up." I asked "Why would Security go in our room before we checked out?" Of course this was wasted breath as she just shrugged.
Finally, a nice lady in business clothes showed up with my (Connie's) stuff still in the bag. Whew.
This is a very nice hotel, and once again I met with someone and let them know I was bothered that they would enter my room before checkout time and make up the room for the next guest!
I have been told before that items such as cosmetics, etc., left in rooms are taken to the housekeeping closet, and in the case of what appears to be valuables then Security is called to remove them and stow them.
Sorry this was long.
As for airports, I figure they save confiscated items to use for door prizes at the Christmas party. LOL.