Originally Posted by
Antarius
I'm really unsure why. I'm yet to hear a case of this actually being a problem anywhere ever. So it seems like a solution in desperate search of a problem.
Lounge showers and some hotels have had this for decades and there is no epidemic of contamination.
Also, I'm not a criminal mastermind, but if I wanted to mess around with fluids I'd put something in the shower head rather than the shampoo... (though I still think doorhandle is the most foolproof provided you have the right viscosity).