Agreed @sanabas, @Krebsy et al., we must not be slaves to convention. But neither should we be slaves to unconvention. The measure must be the effect on the game. And when I'm coaching, or noting points of my colleague for the post-match, I'm as open to the unconventional helping as to it detracting - eyewear helps the umpire see, warm/cool clothing maintains concentration and decision-speed. The moment of truth comes when a player is about to do what they really shouldn't. If getting it wrong means a 10 minute yellow, then they won't do it. But if they guess FH at worst, then maybe they will, and we find out whether the umpire does indeed give just a FH or delivers the 10 minute yellow. That's a big decision, for player and umpire, but a match also sees dozens of lesser try-it/don't-try-it decisions. Because each one turns just as much on "what will the umpire do?" as "can I make it?", an umpire can protect skill simply by looking the part: pre-emptively, before any offences are committed. As the game proceeds, the umpire's performance takes over. A good umpire continues to protect skill by fair penalties, and the hockey steadily improves in intensity and spectacle. A 'pillock' (as they say) gets found out, and play goes dull as players put their skills away, or gets exciting for all the wrong reasons. If your reputation is enough to keep play fair, then by all means wear what others wouldn't. But if a ragged umpire shows up, and the match is unusually messy, then I'd say they were connected. Moreover I'd be pretty sure of seeing specific differences in behaviour between the smart umpire's area and the ragged umpire's area. There is causality there also.