My wife has left the builders alone in the house. Am I being burgled right now?

I'm at work and she just had an emergency and wont be back until the evening. The is are two builders doing our bathroom at the moment - toilet was leaking and then the bath was. Am I right to be paranoid? She thinks I'm being my mother, but I say that that two men who we don't know are in our house unattended. She insists that because they live locally, they are not going to rob us. I say, that doesn't matter. They can change the locks and claim squatter’s rights.

Please, please tell me I'm crazy.