I know someone with hearing loss (who hasn't accepted it yet) who gets irritated with me when I talk to him with background noise playing. Gives me a pinched-up irritated look and says, "What?!". Sure doesn't make me want to repeat what I said.
I tend to let people know about my hearing loss when there's a problem in communication. I'm not comfortable starting off a conversation about my hearing loss when it may not be relevant at the moment.
I also feel uncomfortable when someone discloses my hearing loss for me. I feel it should be my prerogative. I was in a meeting once where I took out my FM device and pushed it towards the middle of the table. One of my colleagues stopped the meeting to remind everyone to speak up because of my hearing loss. My colleague meant well but I didn't really like the attention, and the implication that everyone was somehow ignoring my needs. Personally, it made me less likely to use the FM device if it was going to interrupt the flow of a meeting.