No governmental agency or industry association oversees home exchanges, so unless you are a victim of fraud, your recourse will be minimal. Talk to the home owners you're exchanging with at length. Confirm information about facilities, exchange photos of the major rooms and the property, and ask for references from people they've exchanged with before. Meet them first if you can. Have them show you around the house, eat dinner together, and discuss what you plan to see and do.
Friendship serves as a type of insurance.
Draw up a written agreement. This is particularly important if there is a language barrier. You might want to put in writing rules concerning maintenance of the property, care of the pets, use of the car, which items shouldn't be touched, where smoking is or isn't allowed, what to do in an emergency, and so on. Come up with a contingency plan. Don't exchange with anyone who won't agree to a contingency plan.