I suppose that at some point the crew could become "illegal" (exceeding the amount of duty time prescribed in the regs). Last week I was on a UA flight between DEN and LAX that got sent to the penalty box before takeoff for almost an hour. One of the F/As commented that she hoped that they wouldn't become illegal because of the wait. I asked her how that worked, and she said the timeclock starts once the brakes are released. So time in the penalty box did count.