They do call families first but, as you say, they then let everyone on.
In our case there were not enough seats left for people to sit,so a couple of people stood at the departure gate and that signalled everyone to queue up and fast,it was manic,even though the plane wasn't even there yet!!


We had been to Reus airport before so knew this would happen so we got to the airport a bit earlier so we were first in the queue and then just sat right by the doors.It was still bad but better than if we had left it later.
I'm sure if you do get on late then just explain about your children and i'm sure they'll help you.