How about sending somebody to call them over and casually, subtly (but not too much) implying that pissing off the ref right from the start is not necessarily the best strategy?
You may for instance send down one of the touch judges to let them know they are late and the ref looks pretty pissed at them...
In NM example I said that I would warn them as they left the pitch not to be late and that I would go to the dressing room after a few mins to get them out, only then if they refused would i abandon the game.
Shelflife, I am not sure what I would do in NM very unusual scenario. Perhaps there is nothing that can be done
but in general terms I don't get too bothered if we kick off a little late.
In an extreme case like NMs : as referees we don't have any actual sanctions we can use to get a team on the pitch, other than abandoning the game (a PK would hardly put everything to rights) If I ended up using the nuclear weapon of abandoning I would be very disappointed, and somehow I don't think the 36 players and 100 supporters would watch me getting in my car and driving off thinking "good ref that one , he handled that well"
Fair enough, I think that if you pander to the team that refuses to come out and put the game back 30 mins , you now have 100 supporters freezing in the cold wondering what the hell is going on and you have 18 players frozen to the bone and another 18 laughing their heads off at everyone while they gain a huge advantage. You still havent sorted the problem though and if they are late to come out again it just make the ref look like a total fool to all involved.
By allowing a team to screw with everyone and get away with it , you also create an edge to the game, I know if I was made to wait 20mins on a bitterly cold day and the ref didnt do anything about it I would have no respect for him and none for the opposition, you could be sure that a few sceilps would be thrown.