I tend to insist there are 7 ways for a batter to reach 1st base (hit, walk, error, fielders choice, hit-by-pitch, dropped 3rd, obstruction). A buddy of mine showed me a list of "23 ways to reach 1st base" and at first I said that all of them are one of the seven.
But suppose a spectator rushes onto the field just as a batter hits the ball for what would be a single, and plows into the batter-runner, knocking him down. Of course, immediate dead ball (5-2-1-c) and the umpire can place him on 1st (8-3-3-e). But how would this be scored?
It doesn't meet the conditions for a hit or for obstruction, which is an act by the defensive team.
I would call it a hit by analogy to OBR 9.06(e), which awards a two- or three-base hit on obstruction or other base awards. But there is no analogy for this in NFHS that I can find, and even then, there is no provision for a one-base award. But it doesn't seem fair to charge the defense with an obstruction call either. (Or does this matter since this isn't a recorded statistic?)