Ok, so it's not a big thing, but it gets my goat when people put non AIBUs in AIBU either because they are lazy to find the topic (is Chat really that hard) or to get extra traffic. To me, it's a bit like queue-jumping, which is just not British.
It's also annoying for those of us who have hidden certain topics from active convos, so you'll suddenly find something like "AIBU to ask you for camping tips?" or "AIBU to think baby-led weaning is the business?" when you've hidden those topics.
Every so often, I'll report to MNHQ. Sometimes, they'll move the thread and sometimes they'll reply that, yes, I'm right, but they don't want to be too heavy-handed and they'll leave it.