30Amp plugged into 50Amp?

[5ER]

Question, has anyone used the "50Amp male to 30Amp female" adapter dogbone when hooked up at camp ground? The protection for the 30Amp cable should be your 30A breaker inside trailer. The reason for wanting to do this is because having two 30A breakers in series has allowed the outside breaker to open before the inside breaker and then you don't know if the campground lost power until you go outside and check at the post. It is also easier to reset without having to go outside.