Can a Sitter get in trouble if something happens from an owners command ?

I believe legally you would be in the clear. In your situation, I’d definitely use rover messaging to create a paper trail of that conversation that it was too hot in the garage. However morally and ethically, I just couldn’t do something that I felt would harm a dog or end in tragic consequences (even if that’s what owner directed).

I always do a meet and greet wherever I’ll be providing services to check everything out and ask lots of questions. At that time if there’s something that we’re not on the same page about I’ll discuss it. One example is people that say “my dog doesn’t have to walk on leash or doesn’t walk on leash with me” which results in the conversation that I absolutely will not take responsibility for any dog or provide services for any dog that will not walk on leash (unless they’re not walking outside their home at all), all dogs have to walk on leash if they want me to care for their dog.