Look, as long as what you're putting in your own body doesn't affect us in any way, we're cool with whatever you want to do with your life. We probably wouldn't recommend this, though. There are some fluids which should be kept separate at all times.
On closer inspection, the pictures on the sign make it clear that it's talking about two different things. You'd have thought someone would have thought twice about how it read before they went to the trouble of getting it printed, all the same.