Does your Sprinter have a catalytic converter? I assumed it was diesel and and does not. Our truck camper is more than 10 years old, diesel and does not have one. But at least one of the campgrounds we go to on CA coast <40 miles away warns about portable generator and other thefts.
My son had his catalytic converter stolen while visiting girlfriend who lived in sketchy area of LA. They thieves also damaged two O2 sensors so total cost to get it repaired was ~$2K. It's a Honda Element which has a lot of clearance so it's easy to reach under it from the passenger side and cut the converter. His solution is to only park against curb so nobody can get under it.