I stand corrected in large part. However, I knew my GV goes through in neutral with the engine running. So the manual is correct but here's the trick they use. They attach the seat belt so the vehicle thinks there's someone inside. Then it goes into neutral, engine still running and away it goes. It doesn't t go into Park or turn off. No issues with the rollers. It's picked up when at the end and driven to the drying area.
At newer car washes using the moving matt, they wait until all 4 wheels are on the matt, put it in park, turn the engine off and get out.
When I was at the car wash having this discussion, a fellow with a newer G90 overheard the conversation and asked if whether his 90 had the same treatment. The attendant said "yes" and that several other newer Genesis models have the same issue.