Just listed my property the other day and had some showings but a bunch of people have come due to someone posting my property through Facebook marketplace and Craigslist which I wasn’t using. Telling them they aren’t in town and to look the windows if they want to see it or someone told themsomeone would be there in their place (I was there). Luckily I had caught a lot people and told them what was going on but I don’t want people to fall for this when I’m not there. What can I do about this? Looks like they’ve taken them down now because one person called them out. Could I be in any trouble if someone does fall for it and gives this person a deposit?

Put a big sign in the window warning about the scam and that showings are only done through (whatever your process is).  My agent has a big "NOT FOR RENT" sign she puts in her sales listings because this is so common. 

You could wind up with a "tenant" that moves in, that you never approved, and who got scammed themselves. Then you have a whole debacle to unwind.

@Kevin Means it is a very annoying scam that could have all sorts of ramifications-fortunately it is still uncommon. Say the scammer came up with a key-not that hard actually. They could take the move in deposits and rent and the 'tenant' could even move in if you were remote or went on a holiday. Now someone is living there and you need to get them out.

I think that the only way to prevent the scam is to watermark your pictures and not provide the address in the ad; but that is very limiting; most anyone we have ended up renting to was a drive by to begin with and contacted us afterwards.

@Nicky Reader just got done doing this actually

We have prevented this by watermarking our photos- After a scammer got 2 unsuspecting tenants. 

 Also we post a big sign that scammers on craigslist are trying to scam people and the only number to call is us - our property mgmt company.  Watermarking stopped it

@Kevin Means   You should watermark your photos.   You can get a cheap app for a few bucks and then used the watermarked photos for your listing.   This keeps scammers from taking your photos and re-listing elsewhere. 

I agree with everyone that one of the best deterrents is to watermark your photos. But they didn't say with what. Add your name/company name and phone number, which of course means scammers can't then use their own information.

The second thing to do is to add an alarm system. The best for vacant properties is Simplisafe, because it uses cell phone towers instead of WiFi, which vacant properties don't have. You can buy new and used systems and components on Craigslist and OfferUp to save money. It's $15/month without the app and $25/month with the app. And you can start and stop service anytime you want. An added benefit is personal safety during showings.

Originally posted by @Kevin Means :

Just listed my property the other day and had some showings but a bunch of people have come due to someone posting my property through Facebook marketplace and Craigslist which I wasn’t using. Telling them they aren’t in town and to look the windows if they want to see it or someone told themsomeone would be there in their place (I was there). Luckily I had caught a lot people and told them what was going on but I don’t want people to fall for this when I’m not there. What can I do about this? Looks like they’ve taken them down now because one person called them out. Could I be in any trouble if someone does fall for it and gives this person a deposit?

In the future you can watermark your pictures. That helps a little bit