Wild Yeast?

I have a couple of questions about wine making with wild yeast.

1. Since I add boiling water to my grapes does that mean the wild yeast is coming from the air?
2. I have read that wild yeast dies at around 6% alcohol level. If I use cheese cloth instead of plastic wrap over the fermenting crock will I allow new wild yeast to replenish the dieing yeast and therefore increase the alcohol level?

May be way on the outside with these questions. I think you are any thoughts anyway.

1. if you boil your grapes there is no other place the wild yeast can come from.

2. if the yeast are dyeing because of the ABV new yeast aren't going to magically survive.