It could be hard to get full points because people are sometimes more likely to leave feedback when they have something negative to say?! I'm sure this is not always the case with runners but can be apparent in other areas eg those leaving feedback on hotel/trip websites.
Plus, 100% suggests perfection - perhaps people who grade less can think of one or more small improvements that would be possible and therefore a "perfect" score isn't awarded.
Orienteering races often have a mens urinal wall which tends to work well. They never split mens' and womens' portable loos as this just leads to empty toilets with people waiting. The loo question is tough because they are very expensive and as mentioned here, they are used constantly for a short period of time, then very little for the remainder. In an area where there are fewer bushes and other concealed "natural loos", it's definitely important to have more.
I'd rather pay less for an event and queue for a "reasonable" time, ie up to 5 minutes. That said, it's pretty stressful if you're in a loo queue and you should be warming up or getting to your start position. I don't envy organisers who have to make the decision!
