Window nets slid in on one side on the top, then click in the other end with a seatbelt style lock. They are faste ed on the bottom (front and back) so when loosened up top they just lay down inside the door. Maybe nascar has different rules but thats how my drag car had it back in the 90s.
Cool things they did. Napcar ruined the sport tryin to make all the cars the same. Hasnt been any good in 25 years. Back when a car was a car and not a manufactured entity, it was alot better.
Yeah it gets in the way if you wreck and have to get out, imagine you're a safety crew member and you're trying to pull an unconscious driver out of a burning racecar and you have to spend a few extra seconds fumbling with an invisible barrier you weren't trained to deal with - That's why they have rules like this, because they know the drivers are crazy enough to put themselves in huge danger to run at their maximum potential, so they have to step in and mandate things that force everyone to run the slow and safe option