People manipulate / obligate non-friends by sending gifts of impressive $L to put them on the spot. You cannot decline the gift and you can't give it back if it is copiable.
I got stuck in this last fall by a stranger I don't know why, but I was horrible for objecting. She's been passing along defamatory impressions and while blocked people have attacked me versbally on her behalf.
You don't get invovled with unwanted squabbles but at least you can prevent them by giving non-contact recipients the option to not accept a copiable gift sent from the marketplace.