It's a system here, but as most pointed out, it's not always followed. As to who's on first, what's on second, I don't know's on third ....

. For me once I get my end of the transaction, be it funds from the person or knife, I provide a positive rating for them straight away, easier to do while it's still fresh in the mind. IF something happens on his end and it goes sideways, then that's my problem but the person had kept their end of the bargain and I confirm that with the feedback. Now my dealings I keep as open and as clear as I can so I haven't had anything go haywire so it's all been good. But you'll see that my feedback score from folks is well over a hundred less than what I give, so there is a disparity there.
I put it down to some are not very computer savvy and get confused and just don't bother trying to leave feedback, I can understand that, but some just plain don't care to do so, which can be a tad annoying, but there are far more things to worry about than not getting positive ratings, I do not remind anyone of their neglect, just doesn't seem worth it, but I also think some just flat out forget to do so, we do have lives outside the forum
When I have a sale up and someone pings me about it, one of the first things I do is look at their feedback score, BUT I also look at both what they received and what they gave and if there is a large difference it does reflect poorly, to me, that maybe this person might not be as conscientious a person and might be best not to deal with.
Common curtesy seems to be lacking more these days, the world grows smaller, people are in such a hurry that things can be forgotten in the rush.
"Kindness is the language which the deaf can hear and the blind can see. "
~ Mark Twain ~
G2