In our league, cell phones must be turned off. If a cell phone vibrates or rings during the match, it is automatic loss of point. So this wouldn't have happened in our league.
My own family knows they can't reach me during a match, so they don't even try. I tend to get a lot of calls as soon as the 2-hour block of time is over, though.
-- Random Error Generator, Version 4.0
-- Master Moonballer