The Elmhurst "water" balloon

I tried to explain the phenomenon of P-bags to my friend who lives in another (much cleaner!) town. The item pictured above is a thin plastic bag (think produce bags from the supermarket) full of a yellow liquid that I assume is human urine. I have seen so many of these on and around 43rd Avenue. I passed this one on my walk to the train this morn. It was about 5 feet from the curb, so hopefully a car will roll over it soon and the contents will be expelled that way. I try to do my part to pick up litter, but I draw the line at touching a flimsy bag full of urine.

I have so many questions about these P-bags. No, I no longer wonder why someone would toss such an item, making the neighborhood look really gross and creating VERY unpleasant clean-up work for another person. But I am really curious as to why they choose this particular means of eliminating waste. Specifically:

1. Why not just pee on the curb/against a building, ie, NOT in your vehicle? I assume that it is cab/car service drivers who create these Elmhurst souvenirs. The majority of cabbies are men. Men have the anatomical means to eliminate urine in public places rather discreetly. I understand that cabbies  cannot afford to waste time driving around trying to find a business that allows non-customers to run in and use the facilities. Even the city Starbuckers have started to lock their bathrooms. My question is, why don't they find themselves a not-too-busy street and urinate against the curb? Heck, even if they peed on the curb on a BUSY street they would probably be able to get back in their car and drive off without comment. Just last week I saw a man right on 14th Street off 6th Avenue (in Manhattan) urinating against the Big D's Discount Store; this was at 9am, when the sidewalk was crowded with rush hour commuters and the PoPo presence was strong. Don't get me wrong, I don't want to encourage public urination in my neighborhood; I'm just really curious because I would think that not peeing in the vehicle in which one spends 12+ hours a day would be desirable.

2. Okay, you don't want to risk peeing out on the street. But why would you choose to pee into such a flimsy receptacle? Every P-bag I have seen has been a flimsy, very thin plastic bag: they look like produce bags from a supermarket. Why not invest in a urinal? I guess because then they'd have to empty it and at least occasionally give it a perfunctory rinse, whereas this is a single-use, free item that they can just toss out the car window. But why choose such a flimsy receptacle? I would think that the risk of tears and leakage of these thin plastic bags is very high. Why not pee into a bottle? (some folks do; believe me, I've picked up plenty of Poland Spring bottles full of yellow fluid). Or at least use a regular (ie, thicker) plastic shopping bag that would be less prone to leaks?