My neighbors a few houses down had something similar happen to them. This time, however, it wasn't mistaken identity because the previous owner of that house was a SWF who bought the house right after it was built 12 years ago. The current occupants bought the house from her 3 years ago. Just about everyone in our strip of THs have owned theirs since they were built with the exception of us and the folks above. The guy hasked them if they saw anything they wanted. They left quickly.
I keep our doors locked unless I'm going in or out a lot (yardwork, etc).