Slung the bat

[Tex]

Had a batter who during the hitting of the softball in a NFHS game, slung the bat to where the bat went behind the catcher and hit the fence quite hard. The bat did not slip from her hand. I warned the coach and said, that for safety reasons, the next batter who does this will be restricted to the bench. Two innings later, same batter does the same thing again, with the bat landing in about the same spot next to the fence, as she safely reaches 1st base.

I restricted this person to the bench and a substitute replaced her at 1st base. I have not found any rule (NCAA, NFHS, or ASA), covering slinging of the bat in foul territory, thus supporting my call. Was this the proper call? Please mention the supporting rule I should have used.