When sending of a PM to someone and have the option Request Read Receipt marked. The member you PMed should get something saying give Read Receipt Yes | NO or something right? well it never asks you for anything to do with Read Receipt near does the sender get a message saying it has been read.
I think how it works is if you go to UCP > Tracking, you'll see messages that have been read or unread, and I think that if you deny a read receipt, it will show in the 'Unread' section rather than the 'Read' section, even though it has been read.
Okay well i just tested it that why and it still shows it has been read when it click on the deny receipt.
I use this feature on this site everytime I send a Pm and assumed I would get a PM saying "USER has read the PM: PM NAME HERE". I guess I was wrong, even though I would like to see it like that.