While i generally like the idea of having *something* to separate areas, i think the main problem is that guests are not persistent entities that move through the park. They're just models spawned at different buildings that wander about. One way for me to separate areas has been to not build paths connecting to the main visitor areas, but instead just connect the utility areas with monorails, that way guests very rarely spawn in those areas. But yeah the entire guest system is clunky, i've suggested revisions but it's a big one to fix.