I've noticed this a lot recently, and have been (falsely) accused of it myself more than once (have had a few name changes since)
AIBU to think that this is pretty much the same thing as troll hunting? And in any case does it really matter? The daily fail manage to get enough of their material from genuine threads without needing to start fake ones anyway don't they?
I find it really smug and irritating when someone feels the need to accuse someone when there's no real way of them actually knowing.