I find it funny about people using those called "thieves"...
Which is ironic because low voltages trash things like A/C compressors and other components other time, so if a RV park is chronically running a low voltage and are aware of this (but do nothing except try to ban autoformers), they could be labelled as "vandals" for the damage they cause.
I like having the autoformer (and EMS) inside the rig. Keeps people from complaining and keeps it from disappearing.
As an alternative, I've been thinking of a whole-house inverter of 3000-4000 watts, then having the batteries fed by the usual 30 amp converter, as well as having another converter that is off a 15-20 amp connection. That way, I'd just plug in the 30 amp plug and a 20 amp plug in a CG that has low voltages, and none of my stuff would know or care.