Good point brought up about the 30A Pedestal at the camp ground.
You are obviously going to loading down this 30A service big time and since these get a lot of use by all of the 30A trailers the 30A connector may have been over heated and maybe even arced over a couple of time...
Look for burn marks around the connections and if you see them request another site - do not try to use the 30A connections that have obvious burn marks on them...

Google image
Using this burned socket will make your 30A side of your RV30A to 50A long DOGBONE adapter cord look like this in short order and will need to be replaced...

Google Image
The campgrounds are suppose to keep their equipment in good working order but with all of the high use you can imagine how hard this must be for the campground owners...
Keep a close eye on heat build-up in your cords.
Roy ken