My cat goes out some during the day. Never in the evenings. He has discovered that the back livingroom screen will rattle if he taps on it to get in.
My sister was babysitting her daughters cat last year. Her cat never goes out and is very shy so my sister pretty much never saw it while babysitting. One day when she pulled up the cat was sitting in the driveway so she took it in the house. WHen my niece got home 5 days later the neighbor was frantically searching for her cat. My niece discovered that her cat was almost an identical twin to the neighbors when she found out there were 2 cats in her house.