Some of the day care centre here have swipe cards and entrances where you have to go past a receptionist to get it. I removed my child to a less prison-like environment when a place came up.

To me the ability of parents to wander in and out of the school at will keeps the teachers honest. The school my sons go to only got a proper fence with gates that shut at the end of last year but the only gate that is locked it the one that opens on to a fairly busy road (busy for where we are not a 6 lane highway). I guess if I had a violent ex or something (mad people with guns) I might want more security but they actually manage ex husbands quite well.