I hope I don't offend anyone by posting this.
My theory is... People who do this are seeking attention.
Often when people are mourning the loss of a loved one they seek comfort and support from friends or relatives.
People seek attention for all sorts of reasons and most of those reasons don't make sense to you and I.
I have often seen RIPs on cars for someone the owner of the car didn't even personally know. What sense is there in that?
For instance... Peter Brock was a famous Australian racing car driver. Very successful and very popular.
Peter Brock - Wikipedia, the free encyclopedia
I've lost count of how many RIPs are on back windows in Australia dedicated to this guy.
Don't get me wrong. I appreciate what Peter Brock achieved but I feel people should let him rest in peace but they won't.