How close is too close?

So I was talking to Jordan yesterday, and he tells me he rubbed my tire during the Cameron race 4 times (yes, he actually counted). Cripes! He's already went down once, crossing wheels with me, during training (he was fine). He knows he has a good chance of going down. I'm proud of how aggressive he is riding, but man, I don't want to see him get hurt. I can't imagine how mad Carla would be at me if he crashed because he hit my wheel.