It is quite forseeable that people can be easily 'caught short'. It may well be in circumstances where the public toilets are closed either temporarily or permanently, or in a long traffic jam. People who need in these circumstances to relieve themselves should not face the risk of prosecution when they do so. If the urination is done in a deliberatly antagonisitic way, then it can be dealt with as a public order offence.
It is not right that someone caught short in a place where there are no facilities through no fault of their own can be prosecuted.
its just a call of nature