Electric bikes.

I use a chain and a steel cable on the outside older mountain bicycle but the good bicycle is kept in the covered truck bed...chained and cabled.

You better secure anything and everything. With the drug culture and masses of people desperate to steal for a living there is nothing they won't take if it's not locked up. Sometimes they even break the lock!!!

Don't forget to take the battery inside when not using the bike.

We have a truck camper mounted on a 2016 F250 Supercab. We carry our two Blix Vika folding electric bikes behind our front seats along with our Honda generator. We are fortunate in that we can fit the bikes folded or unfolded along with the batteries, chargers and helmets and still have room for drinks and snacks. Everything that we formerly carried in that space now travels in an aluminum box mounted to our front hitch. We never leave anything more valuable than a picnic table cloth outside when we are away or sleeping. The electric bikes are a fabulous way to sightsee in state and National parks as well as beach communities as well as to run errands.

I have a pair of Ebikes. I do not leave them outside overnight.
They are just too expensive to gamble with. Bringing them in is easy enough.
Generally I'm not concerned about theft. But I don't want to sleep with one eye open or be on alert for every mysterious sound I hear. So I have just been bringing them in.

I usally bring 2 scooters. I just lock them together at the campground and leave them behind the camper. No problems yet.

I’ve never worried about theft while in a campground. We regularly take bike that cost well over $1000 each, and have only locked them on an overnight at a hotel.

I have heard of programs people put on family member's phones that let them pin-point where other phones are. Wonder if that tech could be hidden on a e-bike? Locate, meet LEO to recover.

We keep ours under the front of the camper and lock them together, we also leave the battery attached, requires a key to remove it. If rain is predicted they get covered. Had them over a year and they are still working good as new. They are the EG Geneva's and we really enjoy riding them.

Had them for years. Store them on the side of the RV overnight covered with a tarp which keeps them out of view and protects against the elements. We always stay in commercial campgrounds if that matters.
If you want to lock them to the RV I would suggest a linked chain which is very difficult to cut thru even with a grinder.