Sadly, it's either slots to prevent you from drinking from your helmet but, letting in the gummint's radio waves, or no radio wave induced brainwashing and overheating which can be alleviated somewhat by drinking out of your helmet which is likely to poison you. Which, by the way, is a deliberate gummint policy to force you to get slots in your helmets. Simple, really
The radio waves? They are beamed down from those black helicopters.