To date, I have queried four different EV manufacturers about towing 4-down and all said it was not advised but could not say why. I know why hybrids don't like it.
One was a real engineer, and allowed as how it should not be damaging, but might void the warranty. It was he that I asked if the regenerative braking could be possibly be controlled remotely. He seriously thought I was joking and they I explained our position and issues.
Wouldn't it be nice to arrive at the end of the day's travel to a fully charged EV Towed??
Now we just have to get someone to listen. But I couldn't even save S&T or SA so I'm not going to dream.
Matt