I would say that Laptops on checked bags have very high chances of not making it to the next destination, especially when your bag is on hold for 24 hours. Who said it was TSA - in 24 hours your bag goes through so many hands and carts so there are so many opportunities for any baggage handler to take it out. I would say it would be pretty stupid for a TSA agent to take the laptop out and put the note inside.
When TSA inspect your bag, they sometime seal it with a plastic ribbon - was the bag sealed when you got it?