Yes, I am a Power Cheater.
When faced with no 50A Socket on the power pedistal I am able to suck in enough juice from a 20A and 30A circuits or two 30A circuits to handle most of the needs of my all electic coach.
Here's how I do it. Ask for permission of the Campground Host first. They may ask for an additional power fee.
First, lets take a look at the 30/50 DogBone adaptor we all use when faced with only 30A service. Figure 1 below shows that within the 50A socket, the two Hot Legs are tied together applying 30A to both Leg 1 and Leg 2. In this configuration your coach can draw a maximum of 30A before tripping the breaker on the pedestal.
By using a Power Cheater Cord as shown above in Figure 2, you are able to combine two 30A circuits or a 20 and 30A circuit to deliver extra power to your coach distribution panel (Figure 3).
You'd think 20+30=50A Service or 30+30=60A service... Not so, with true 50A service each leg has 50A available whereas with the Cheater you have a maximum of two 30A Legs.
If your coach has 3 CruiseAirs (two on one leg and one on the other) you can only run one on each leg. Two on one leg draws more than 30A and will trip the breaker on the post.
My Liberty has 2 CruiseAirs, Washer/Dryer, Charger and Water Heater all on same leg. Way too much for 30A so I have to give up something to stay below 30A on each leg.
While it's not 50A, it is much better than only 30A.
If your coach has 240V appliances you must be sure that the voltage between the two hot legs on two input circuts is 240V or those appliances will not work.