Someone's house - No, private property, but if I was desperate and there wasn't another one close I'd ask.
Hairdresser - I'd ask if I was desperate, but as it's a seperate entity I wouldn't be in there in the first place.
Tesco toilets full - I'd have to wait. Same as all the toilets in use on board I'd wait but as soon as one becomes free I'm in it.
Now, if Tesco had Clubcard Holders Only toilets and the non-clubcard toilets were full then, yes, I'd use them.
Or, would you like me to just go in the aisle? Or risk a severe medical condition by holding it in for too long?