Well said HD... I was just about to chip in with that.
I work in a very large factory where nearly everyone wears a Hi Viz (because, it is true, you actually can't get hurt with one on... no, really!
); so when the fire alarm goes off, or something else noteworthy happens it gets interesting to try and find appropriate person!
Solution: different coloured Hi Viz. Everyone wears yellow, except Fire Marshalls who have red, First Aiders who have Green & Security (who also provide fire & ambulance) have orange and yellow if they aren't in fire kit!
Sure Popham could solve it easily by just buying a different coloured tabbard for the marshallers! I'll leave the ATC subject to someone better qualified.