From one towbar manufacture I just picked model and make at random:
From Roadmaster "NEVER BACK UP WHEN TOWING
YOUR VEHICLE
Backing up while the towed vehicle is attached, will
easily "jackknife" the vehicle being towed. This will
result in damage to the towed vehicle, hitch, tow bar
assembly, and/or motorhome.
Roadmaster, Inc. assumes no responsibility for any
damage that is caused by improper use. Backing up
with a towed vehicle is considered "improper use".
http://roadmasterinc.com/pdf/85-1364-02.pdfSome people wait till inside the "gate or campground" before they unhook to prevent extra vehicle charge if any. Some campgrounds if you come in as "one" unit they count that as "1" vehicle even though it is 65 feet long.