This hasn't happened recently, altho it has happened on several occasions...and not just by me either.

Come home at night - unlock the door and come in - then go about whatever business needs to be taken care of and then relax for the rest of the night. Get ready for bed and make sure the doors are locked before turning in for the night. Come morning - get up and let the dogs out, and find the keys still in the lock from the night before!

Good thing I don't live in a populated area. Someone see the keys still in the lock??? Hey - no need to break in - just use the key - and when you're done, just take my car too - the keys are on the same ring.