"It's just one of the rules of ghosts, back home." You haunt where you died. For a given definition of death anyway. One ghost did leave the school, and that was who Maddie needed to have a chat with. About boundaries. "I take one step off the grounds and find myself right back in the boiler room."

It helped that, the person who mentioned fake IDs, wasn't visible to most of the city and therefore if you keep it cryptic nobody has to know the topic. Her town didn't have much use for fake IDs, getting alcohol for parties was easy enough without one. Just had to know the right people. Her douchebag ex boyfriend being one of them. "Wouldn't know, I don't drink. When I was twelve I tried some of what mom was drinking at it was straight whiskey."

Also 'what mom was drinking' was an omnipresent sorespot of her life. So after that curiosity backfired horribly she'd been too busy cleaning up to ever feel that need. Even while dead. (Not that there was ready access to alcohol trapped in a school as a ghost.)