Because it can't get her pants off.
Oh nooo, what is going on.Dog owners X girlfriend?? Her head is on the spot where another dog peed earlier; her synthetic perfume smells like something a dog should pee on, there are no fire hydrants or car tires around...??? Some dogs like to pee on expensive alloy wheels and she has an earing that smells expensive.
No I think most dogs smell the place first before they pee all over it.I think you have it backwards. Why would a dog NOT do that? Dogs will pee on anything if the mood strikes them. It is in their nature.