My last house was serviced by RCAs. One had a Subaru Outback with a system of gears and pullies that let it be driven from the right side without removing the factory left side drive. Another had an actual right hand drive vehicle, probably imported. There's likely a small but strong demand for right hand drive vehicles that happen to end up in the US with RCAs buying most of them.

A few simply had two people in the vehicle, one driving and the other placing mail in the mailboxes.