Are the Makeup Brushes Really Disinfected?

Today I stopped at Macy's to get a few things, including some new makeup at the cosmetics counter. Even as the woman was applying the lipstick I was wondering how sanitary this entire procedure actually is. Sure, they spray the brush with something right in front of you, and yes they spray the tube of lipstick too, but does that really work? What is in the spray? Is it water? Is it alcohol? Will I accidently ingest the alcohol that is left on the brush that is being swept over my lips? Now, I've accidently read Web MD news headlines this evening and there was a piece on two new strains of the Norovirus. Can the flu spread through makeup brushes? I googled this last phrase but did not find a conclusive answer.