It really was different back then. The folks working the theater were often teens themselves, there was like 1, maybe 2, adults in the entire place, but it was safe, we all knew where the line was, they looked the other way for letting in kids through a fire door or going from 1 screen to another so long as it was kept under control and you were spending money anyway.
Theaters in "indoor" malls were another big one, as we would often be left to roam the mall for HOURS, so food court/theater/hit some stores/flirt with the big boobed girl at the ice cream place was a weekend ritual.
And before cell phones you just had to set a time and a place for pick-up. No checking in, no constant surveillance. Maybe a dad hanging back in the rear of the theater just to make sure no hanky panky was going on if girls were involved.
Once I was 12 or so I could just take my bike and ride the couple of miles to the closer theaters. Across a few highways in the commercial district.
These days it would be dodging kidnapper vans every 20 feet, but back then we KNEW to avoid the run down van with "Free Candy" scrawled on the side and that was all you needed to know!