Stupidity: When the birds gather in the schoolyard, Melanie runs in to warn Annie. Rather than calling the police or fire department for help and then shelter in place until aid arrives (which would take about ten minutes), they instead decide to make a run for it with the children, out in the open, getting attacked by the birds. As it's the 1960s, the schoolhouse presumably has a working phone.
Stupidity: When the Hilts discover they're 20' short of the trees, why wouldn't he "dirty up" his white/light tan pants so the tower lights wouldn't expose him so easily?
Suggested correction: Because he would look scruffy and dirty once he got out. He was the Cooler King and knew his way around after all.
I would suggest in the reality of the escape, light colored clothing would not have been worn so as to blend in to the night and the surrounding environment better. The light slacks were strictly for artistic reasons.