No, not a warning at all, sometimes it's can be a friendly 'hello' which can sometimes help a thread stay on track or help folk to remember the talk guidelines, as Hassled says. We apologise if we've hinted that anyone is dodgy, that was never and will never be our intention.
I know I am not terribly quick on the uptake, but I can't be the only person who finds it really confusing?
When you just post 'cough' do you mean the OP is dodgy, that someone is getting cross, that you think both sides should play nice - what?! And does it count as a warning if someone 'ignores' a cough (because they have no earthly idea what it's about and don't realize it's aimed at them?).
I can see it must sometimes feel to you as if it's completely obvious who is out of order but if it were that obvious to everyone posting you'd have no job to do!
I really don't mean this in a nasty way and hope you won't take it as such.