On the morning it's just easier to go in the sink. This way I'm not pissing all over the floor.
If your toilet is too low to the ground, it also usually winds up on the floor, so I'll just use the sink.
People also spit their fucking gross toothpaste in there. Urine is technically sterile. Spit is, infinitely less so. If you're going to use a sink filled with water to wash your face, you should probably clean the sink regardless
Though I agree. People who shit in sinks need to be sent away
I'm an electrician by trade, but was a plumbing apprentice way back when. Interesting theory you got there, but no.. You can wash all the piss out of the p trap by running the water.