First, the ESP is not a warranty. I'll keep harping on that as long as folks persist in calling it (incorrectly) a warranty. Second, Magnuson-Moss does not cover ESP's, it only covers original factory warranties. The ESP company can void the coverage for any of the exceptions noted in the service contract, and they often do. Third, the dealer can verbally promise to honor the factory warranty or the ESP even though the failure isn't really covered, but the promise is unenforceable. Sure, he can submit a fraudulent claim, but he doesn't get the last word on it. Harley (factory warranty) or the ESP company has the final say, and they don't give a hoot what the guy in the dealership promised you. Unless that dealer is going to guarantee in writing that he will cover the cost of repairs if Harley or the ESP deny the claim, his promise is useless.
Read the entire ESP contract (get a good magnifying glass) and make note of all the requirements and the loopholes. For instance, you will find they can void the coverage for general things like nonstandard parts, or certain specific activities like trailer towing. Does that mean that no one ever gets away with having something covered that really shouldn't have been? Absolutely not. Harley or the ESP folks don't inspect every bike that goes to a dealer for repair, so some claims for things that shouldn't be covered do get paid. The entire thing is a crap shoot, just like going to your friendly casino. So just because several guys will chime in here and tell you they got their heavily modified bike covered, that isn't any kind of guarantee you wouldn't have the opposite experience. You pays your money and you takes your chances just like anyone else.
Jerry