What do you do when clients don't tell you the full truth?

Unfortunately you can't prevent it. On top of owners wanting to present the best version of their dog, dogs will almost always behave differently in a new environment than they do at home.

I never trust a dog alone until they have proven themselves deserving of that trust. I use crates and baby gates to keep dogs contained when I have to leave the house or leave them unsupervised for any reason (even when I take a shower!) I also strongly encourage owners to drop their dogs off at a time that I can be home with them for at least 2-3 hours before needing to step out for any reason. This allows dogs to adjust to the new sounds, smells and place in general, while I'm there to provide treats, pets, and overall comfort.

Final bit of advice is not to leave anything out that a dog could get into and make a mess of. Food, papers, shoes, even blankets and pillows can all look like tasty chew toys in the right situation.

It looks like you're a new-to-Rover sitter, so I'd suggest reviewing the other questions on this board and continuing to ask your own! Best of luck!

No client tells the truth. Partially, because they can't. How their dog acts with them may be radically different than how it will act with you, or at your house. (Then there's always our own prejudice, I mean MY dog is perfect! lol) This is why meet and greets on your turf are important. Dogs may act great on neutral territory such as the dog park but then become a hot mess when on your territory.

Dogs are very inquisitive and smart and sometimes get into trouble in a new environment simply because they are trying to get to something that smells delicious or because they are bored. If there are no signs of destructive behavior at a customer's home or according to what they tell you, it's still a good idea to play it safe and treat the dog like you would a newly adopted dog you introduce to your home. If you need to leave your home for a brief period of time, I feel the safest thing for the dog (so they don't get into anything that could harm them) and for your home is to put them in a crate with a treat.

I am in the same boat as you right now... I have had most behaviors come out during meet and greets and have been able to deny the client then. This time I did the meet and greet and it went well but the dog started marking in my house, on my furniture and even tried to mark my dogs and cat.. I brought it up with the owner and they didn't really seem to care. What I am doing now is just crating the dog all day and giving it breaks out side and then putting it back in the crate immediately. In my experience some people are just going to lie unfortunately. Can you crate the dog or shorten the booking?

I try to make it very clear at all meet-and-greets that it's important for clients to disclose ALL bad habits or unusual behaviors so that I can be well prepared. I want us both to be confident that I'm the right sitter for the job and nobody runs into any negative surprises.

Since I started phrasing it that way, I've managed to avoid mishaps, but a good sign they're not being honest is glancing around the home for any signs of damage during the meet-and-greet. For example, I recently had a repeat client who insisted her dog was now fully house trained in the new apartment, but who (like yours) later said that some behavior I brought up was common (ripping up trash bags, chewing up treat bags, ripping pillows, etc.) despite not warning me at all. Had I visited her new place before accepting the booking, I would have seen broken blinds, chewed up windowsills, scratched up doors, etc.

You could potentially discuss adding a charge (usually I set it up as if it's a new booking) but that assumes the owner will be responsible and compensate you for the damage. If this is something you plan on doing part-time longterm, I recommend drafting up a contract for clients to sign. It might be worth investing in a short consultation with a lawyer (here I found one who did this for like $25 for 30 minutes). Clients who know they'll be expected to replace anything their animal damages are much less likely to omit details about bad behavior.

I'm sorry you're dealing with that, though. It's frustrating to deal with owners who don't respect your home or peace of mind.