I did once. I was young and broke and I saw another apartment in my same building on craigslist for less than I was paying. Tried to call my landlord (who was one guy and not a giant Corp) but he wouldn’t return my calls. So I sent a check for 50 bucks less via certified mail - he called me the moment it arrived and let me get away with it. That apartment was 550 and a drop to 500 made a difference for me then. Now… That same shitty apartment probably rents for 2k a month.
I think the exception proves the rule though so I won’t make you eat any paint chips.