I remewber this happening when I was in high school during a JV game prior to our (varsity) game. The visitn gcoach would send a sub to the table, and then pull him back.
I seme to recall that the official said if we buzzed the horn for himprior to the coach telling him to come back, the sub had to enter. Of course, I'm not sure if that's actually supported under NFHS rules.
I don't like that one case play either. If you had an OOO, he or she could call a T on just about every substitute in the lower levels since many subs in youth-level ball need a "friendly nudge" to get them to enter after being beckoned.
