re: Things you did in high school that would absolutely get someone arrested today?

riding around in the bed of a pickup truck with a cooler full of water balloons then unloading on the first walker/jogger we came across

Also,

A group of wealthy citizens established a social club and built a large club house cabin on a nice private wooded property, with a bar and pool tables, etc., and a swimming pool. One of the guys' parents was in that group and he would swipe their keys and let us in to the club late at night to go skinny-dipping with some of the cheerleaders. One girl was a state champion gymnast. Two others were 5'10" identical twins who won beauty contests, sometimes competing against each other, though I couldn't tell them apart until we were seniors, when I discovered that one had a small freckle the other did not.

Dine and dash

Mooning. I used to drive a car while my brother and his best friend would moon people from the back seat.

Everything

People used to bring their bows and we'd go behind the gym and have target practice

Getting shotguns out of the truck and shooting at doves behind the baseball field

This wouldn't cause an arrest, but it is a funny story. This guy who was a senior had two weeks to graduation. We were sitting in some science class, and he was sleeping. The teacher crawled his arse, and he got up and said "frick this shite. I'm done." That room had these high windows you could crawl up on the window sill and jump out of, so that's what he did. We all got up and ran to look out the window. He jumped in his 79 Trans Am, and squealed out as he left. Our teacher was standing by his desk and asked us to tell him to get back on the room. We all said "I don't think he's coming back Mr. Carter". Dude wasn't smart, and he didn't like school, but damn he was almost to the finish line. He never came back.

8th grade we put freshly caught minnows that morning on a classmate's sandwiches at Landry Jr High/High School. Word got around the entire school by lunch and everyone stared at him as he entered the lunch room. He had the first sandwich then halfway through the second saw half a minnow hanging off a piece of lettuce and puked.

11th grade we, Mu Alpha Theta math club, held a raffle with a classmate's name pinned to the side of the box raffling off his portable color TV. Three keg party at his house that night with his parents out of town. It was really the senior boys in the club's idea. They all ended up being doctors, lawyers or banking consultant. The oldest of us was 17 and Schlitz distributor owner rolled out the kegs for us for a party for "parents"
9th and 10th graders is who bought up tickets right and left with their lunch money.