Only a trained professional should apply a tourniquet. Everyone else should limit it to applying pressure to stop bleeding. And the breathing part of CPR has been dropped, so that now only the compressions are advised - the breathing part is what most people are more likely to get wrong. There are a lot of ways that people can end up causing more problems by trying to help, and the more a person knows how it can go wrong the easier it is to be concerned about that sort of thing.

Given that this is theoretical, why not just take a moment to give thanks for the fact that you haven't had to have complete strangers giving you emergency aid? And leave it at that.