When we were in France we were approached by various productions looking for expat accommodation owners to take part in their shows...Gordon Ramsay's outfit was one - looking to film a series where he visited restaurants owned by expats in France/Spain to help them out. We said a bit fat 'NO THANKS' to that
Then 'Living the Dream' people emailed us, also 'No Going Back', said no to all of them. We'd had contact from others who'd taken part in those shows and had regretted it bitterly. Yes it's free advertising in a way but at the cost of being made to like complete numpties
I think it can go either of two ways. Either the owners come across as numpties and do their business harm, or, they come across as really nice people and even if their business isnt the one that wins, they gain business because of who they are.
But its a risk you take I guess when you sign up for these things (plus you need to be aware of editing/being talked into saying things about the other couples that you dont really want to say)