To be honest, I have no direct experience with that issue. I'll ask around to see if anyone other teachers have encountered it, but we're unlikely to know how it would be seen/received on the law school admissions end.
I very much doubt that it would be as dramatic a disqualifier as you're fearing. I would recommend that in your addendum to any law school app you just explain the situation you just described to me.
As long as you do that, I think they will still consider your app the same way.
It's sort of like soccer: no one thinks someone who only gets ONE yellow card is a dirty player. It's possible you just had to be warned for being too careless with your slide tackles.