Flying 481 LAX-SFO. About 10 mins ago post-safety demo, FAs came on to announce a groundstop at SFO and a 40 min wait before any further announcements. With a 30-strong group of schoolkids on the plane who are reportedly meant to be connecting onto an SFO redeye, this news went down like a scene from Lord of the Flies. FAs have valiantly hidden themselves in the F galley. Sundays on UA have become my worst nightmare.