During the short time I actually practiced the 'black art', there was a guy who figured his meet time, then cleared an A/C through another's altitude at that time. Problem was, he forgot to add the required 10 min as per the sep standard. So, on the freq comes LH, 'now leaving 350 for 390, just passed our traffic.... btw, you guys are really good!' . Needless to say, that guy was taken out to the woodshed....
