You might want to thump your tardy teammates for bad behavior, but if you do, don't tell anyone, or you might get charged for assault.
I didn't pick up from the first post that it was a 'team' event. well, the organizers are free to set tournament rules, and, (normally anyway) as long as those are publicly posted and advertised, all who enter the event are acquiescing to the rules for that event.
well, either
a. choose your teammates wisely, or
b. take potluck, or
c. don't enter the event... simple enough.
The Olympiad regulations (availble on the official website, though you have to dig for them) say:
"The beginning of the playing session shall be announced by the Chief Arbiter or by a single acoustic signal. At this instant, any Player who is not seated at his/her Match shall be defaulted immediately. Where both Players are absent at the beginning of the playing session, both Players shall lose the game by default."
So yes, it's true. Whether it will be strictly enforced remains to be seen. If it is, we can expect a lot of forfeits, at least in round one.
Part of the reason for the introduction of this regulation is surely the game Short-Baramidze from last year's World Cup. In a 25 minute tie-break game, the jet-lagged Baramidze overslept and arrived 24 minutes late, leaving himself just one minute plus the increment to play the game. Despite this, he won. Short said afterwards that he had been put at a psychological disadvantage by the incident (I can imagine how: you relax mentally during the delay, and then find yourself having to play what is almost a different time control to the one you expected).
Short's comments on this at http://www.chessbase.com/newsdetail.asp?newsid=4290 are quite interesting. He does say that "a certain amount of leeway should be given", which I guess most players would agree with. To have none whatsoever is perhaps a bit odd.