To pee or not to pee ..... that is my question?

Generally, both.  Though enforcement in either case is somewhat spotty.  Use reasonable discretion if you choose to do so.

Or pee on yourself.  Odds are you won't be alone.

If anything, stop at the nearest port-a-potty.

If near a house on the course and the owner is outside and they are a race fan, ask them if they'll let you use their bathroom if you can't make it to the nearest port-a-potty (or maybe they'll let you sneak to the back and whizz (not Whizzzzzz ).

Else, have a filled water bottle available to squirt yourself while walking along tinkling in your tri-shorts (I've done this during a HIM).

Oh the swim! That part of the race that I take in so much
water I have to pee on the bike.

I think generally it's "accepted" and I don't think I've ever seen a race where somebody wasn't peeing behind something.

However, I do want to caution about all the crazy laws that are out there now.  In many states it's more than just peeing in public, it can be considered indecent exposure or lewd conduct which are serious infractions that can result in your name/picture being placed on that fancy state run website.

So, I'd strongly recommend finding a portable restroom. 

1.  Plan your hydration.  Drink up the day before, and that morning a couple hours prior to the race, but not much in the last hour or so.  Pee before the race starts.

2.  Depends on the location.  I run on rural roads.  Stopping to pee in the woods is no big deal.  Stopping to pee on the side of a building in downtown phoenix during the marathon with thousands of specators and runners- that's a tougher one.

I'd say that the answer to this question is very situation/location dependent.

1. The meaning of life

2. The chicken or the egg

3. Peeing on the course

4. Women and clocks Socks disappearing in the dryer