They started boarding by seat row from the back but by the time they got to row 20 they gave up and it became the usual scrum to get on.
It's crazy, either do it, or not. These half-arsed efforts don't serve anyone at all.
I find the same in supermarkets. Outside, people dutifully observe the distance markers but, once inside, revert to standard behaviour. The other week I was at petrol station and they have installed a Stop/Go traffic light at the door that counts people in and out. When I got there it was red. So I stopped. A man asked me if I was waiting, I started to say, "I'm waiting for the green light" but after "I'm waiting ..." he overtook me and went straight into the shop with no mask on.
Shopping centre this afternoon, dutifully following the one-way arrows (very large, very obvious) like a good boy and there were groups of several people coming the opposite way seemingly oblivious to the cross-contamination risk. Strangely they were either ch*vs or other persons new to these shores. Couldn't care less it would seem. Makes me mad, but you can't change stupid, you only waste your time and energy trying to explain.