I'm new at this, but I'm guessing that there isn't a way to just do a meet and greet without a potential booking, since those who just want to meet sitters for some time in the future would likely want to book you outside http://Rover.com.

So far, each of the new booking requests have requested a meet and greet to see my home and make sure my dog and theirs get along, but each one has ended with a booking confirmation.

Pat