I had a neighbor who did something similar once. He came over and asked me if he could hide his car in my back yard so he could catch his wife cheating. I let him park his car then he went back and crawled under his mobile home and spent all day there. His wife saw him crawl under in the morning and said she spent all day thumping all around the house as much as she could and making as much noise as she could then went out in the late afternoon and leaned under the house and asked him what he wanted for dinner. They split up a year or so later and in fact she did have a boyfriend on the side and moved in with him immediately.