The only time I had an issue peeing in public was at a concert that was delayed for rain, and they made us all go inside because of lightning into this tiny building. (But I am sure the people count in the building was way against code, but safer than lightning outside, I guess.)
Anyway, we were inside so long that the women started using the men's restroom, too, and I tried to pee and there were literally a dozen women in line who were all totally watching the guys pee; they weren't even being discrete about it. It was my turn to go and I saw three women starting right at me dick and I couldn't do it. It had the urinals that went into the floor without sides, and if I leaned forward enough to not be seen, I would just be peeing on myself.
The strange part was my own reaction. I never thought I would be shy to pee like that (I have peed in front of friends before and such), but I think it was the total unfairness that women got to stare at guys that blatantly and if we men watched women go we would have been in far more trouble. I admit that I was jealous of the handfuls of guys who peed without any issue of the women watching them.
The crowd was younger...mostly all 18 to 20-something hipsters at this place, and we already felt out of place being in our 30s at the time, so maybe those younger folks do stuff like this all the time? I don't know.
(I also saw a woman tell her husband to just hold it because she didn't want any of the ladies in line staring at him! Poor guy.)