This is not a pet sitting scam, but still is one that pet sitters should be aware of.
This morning one of my friends told me that her parents were being used for an apartment rental scam. In this case, a scammer found their information about their "house for sale" on craigslist. The scammer then made his own craiglist ad with the house for rent. People called and gave personal information (including pictures of themselves!) so he could "check their credit history". Then he told them he would be going out of town, but that they should just show up on Oct 1st, and the keys would be on the table for them ready to move in.
Looking this up online it appears that often the scammer will actually be someone that will visit the house and physically collect money and things like that. Since pet sitters often arrive at homes alone, and at various times through the day, this can be a risk to our safety.
When you have clients that are in the process of moving or showing the home, consider:
Asking them to suspend all showings until they return, and having any keyboxes removed during that time.
Be sure that all windows and doors remain secured. Check that there are no obvious broken windows each time before you enter a home. A flashlight is a great tool to use at night to check from afar.
Watch extra carefully for unexpected vehicles when you arrive, and don't be afraid to call for confirmation if anything looks out of the ordinary.
Leave the detailed "Who to contact in case of emergencies with the pets" paperwork out in the home (the form is available in the Library Area) so that anyone who does visit the home sees that the home is being visited randomly throughout the day. This may greatly deter return visits.
It also doesn't hurt to do a quick search on craigslist to make sure the house isn't listed multiple times, or with different contact numbers.
And always, be aware and keep yourself safe!