There's an access road at the back of my garden that leads to garages.
The amount of people who think the access road doubles as a toilet is unbelievable.
I am absolutely sick of teenage boys from the school across the road leaving school every day and peeing in the access road. They've been out of school for less than a minute, they've walked maybe 100 yards, they all live locally, there's no need.
I walk my son home from school and we pass the access road. It can be seen from the street and there's not a week goes by when we don't find at least one teenage boy peeing there as we walk by. They don't care if they are seen, and are often unzipping themselves before they even reach the access road.
Often they are peeing on our wooden gate.
I can understand a young child having to go to the toilet outside if the queue was too long for them to wait, but not teens or adults.
I would be annoyed at what you have described OP.
I would not want hundreds of people taking a last minute wee just a few yards from my garden, all at the same time, and I would be complaining to the event organisers, the charity, and the council about it.
I think you are lucky the residents are not all standing there in the wood taking pictures to report you all to the police for public nuisance.
The organisers need to provide more facilities, and if that means less for the charity then so be it.
I really don't think the 1000's of people or businesses would be happy if the runners were weeing in their shop doorways, car parks, or on the pavements outside their homes or businesses.
Be honest, would you be happy if this was happening on an annual basis outside your own home? Bearing in mind they probably have an admittedly much smaller amount people weeing out there on a daily basis and no doubt have to cope with irresponsible dog walkers as well. And you could probably see it happening from your upstairs windows, and smell it in warmer weather?
Would you be happy to put up with that day after day and then have hundreds of people all turn up at once to use the same place as a public urinal and be told to get over it because it's a one off and all for charity?