Does this drive anyone else nuts?!

When my son starts getting over stimulated, needs to nap, or just when we want him to be covered we put him in his car seat with the cover over. However, my in laws don’t care if the cover is on and will yank it down to talk to him anyway. It bothers me because 1. They don’t ask 2. We have him covered for a reason and 3. It keeps stretching out the cover. Advice please? Or just others bothered by this?