Even when there is an SNCF person checking your tickets at each carriage door, I have never seen any of them help a passenger with a suitcase. OH&S issues.
I can't see where anybody in this thread has suggested that train crew touch or move passengers bags around.It's passengers themselves that often have to move another passengers bag to make room on the rack for more luggage.
If you can find them, the Big Yellow Tags work very well for identification purposes.
Helking, read back to the start.