I've done a couple on roro shipments recently, one ex Bremerhaven, the other ex Portbury near Bristol. Both times the shipping agents made it clear that anything not bolted down and a permanent part of the vehicle was at my risk. The vehicle is unlocked at all times, so its possible for anyone to have a look through you gear whilst on the wharf, on the ship or before you take delivery at the receiving end.
The ease of roro is that usually its just a case of doing the customs bit and port charges at the wharf and then driving the vehicle away.
With containers, in most cases, the container is taken away from the wharf and unpacked at a freight forwarders. Usually that one movement increases the paperwork, your effort and costs by a lot more than you will have been quoted.