A referee at a tournament etc:
Your word is final, no argument (the captain can raise a problem with the ultimate - but the decision still stands)
It is the players responsibility to make sure they are clean - if it was from a previous game that's their problem - and that whole team needs to learn to check each other
But I suspect you are at a punter game, especially referring to keeping the customer happy.
A Marshall is there to observe and keep things safe, rules are down the list of responsibilities , customer satisfaction is also high on the list of a punter Marshall
So point it out, he claims it is old, point out that he ought to have cleaned it (and if you have any belief in him remind the other Marshall's to have a glancing look over players before games - a goggle hit is obvious to the observer)
It's your call at the time -
Let him off and remind him to clean,
sorry mate, I just see the hit and the paints still thick, if it had drilled more and thinned out then I could accept it
Or a 'customer compromise' - if it's a respawning game (also which could have players not cleaning off) tell him to go just as far as that tree over there instead of to the normal spawn point
However if things kick off (and some people will kick off purely because you say they have a hit) then it cannot be acceptable
It does not matter if you are 15 or 50 as you should not be doing anything physically anyway (that only comes into you or another player /Marshall being assaulted)
The only thing with you being is the less 'life experience' and confidence you may have, so can feel out if control of the situation, be in fear of some people or not balancing assertion and aggression. You require assertion, with that it does not matter how old or how big you are.
If he's kicking off then there are 3 choices - he stops and listens, he sits in the safe zone to calm down (for the rest of the game or missing a game) or he goes home (the final option includes the co-operation of the manager - which should exist, but will depend on circumstances and for most probably be a choose of the last 2 depending on what happened and the player by the time you all get back to the safe zone)
He may be a paying customer but he has not paid for the right to abuse staff
