Mostly everywhere cabin colleagues are trained. That includes the concept of sterile cockpit during taxi-out, the meaning of "seats for departure" call or similar, and the rejected takeoff drill. The necessary insight on tasks and workload of the pilots is included.
They won't call the front office just for losing facebook connectivity on their mobiles. While the practical application would vary should the day come, a CC call to FD during the roll below 100 kt is a good trigger to reject.
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The original picture that started this thread is non-environmental icing - upper wing frost. And about the most severe case I remember ever seeing, flying the same type for a few years. The next morning after this thread started, we de-iced for the same phenomenon except due to only 1/4 cover compared to the pic above (going would be still illegal). By the our crew arrived at the A/C after an overnight stay, the de-icing equipment was already waiting without being ordered, such clear cut the case was. Judging from the fluid patches all around, several planes got the treatment and had departed already.
