How would it slow the natural combustion of lower octane fuel? Alcohol actually burns cooler. Knock is caused by heat. Ever notice how a car runs better in cold weather? It's cause cooler intake temps = more power. So just think of the possibilities of injecting alcohol into your intake that drops temps so low it actually creats condensation on the runners. It allows you to run high boost with low actane gas cause it reduces heat. All knock is is heat. Thats how you burn up a piston.

Yes it is safe, alot of drag cars run strictly methonal and there are quite a few dsm's doing impressive things with alki injection.