maybe you need to give it a go her coming and baby sitting at your house to see how it goes. Your concerns may be unfounded.
I can understand however. My MIL cleans and reorganises when she goes to my other SiLs houses. To the extent of resorting their clothes drawers :what: although it comes from a lovely place its way too ott for me. I dont believe you should ever open someones cupboards or drawers without permission. Boundaries!