LozCooper wrote:You could always try phoning your opponent on the off chance he has his mobile switched on
Would that be done anonymously or not? If the number showed up on the screen, I suppose the opponent could show the arbiter that it was his opponent ringing and/or plead extenuating circumstances ("my opponent was ringing to say he would be late"). I suspect it would end up as a double default (and none of the other players could complain that it was disgraceful that no-one got awarded any of the points - though possibly some might try in some circumstances).
I have, when ringing a captain to say I will be late, made sure I've done so before play starts. Ringing your captain and causing him or her to be defaulted because his or her mobile rang when you called might cause discontent within the team! Though when captaining a team myself I have, when players are late, asked opposing captains and my opponent to be allowed to step outside and check my phone to find out what the latest progress is with a late player, and they've never objected.