Well, seek on the advice of several of my online colleagues in the urinalology field, online we at the ICBE have conducted extensive research with respect to public washroom facilities which are equipped with the trough. We did not actually successfully locate such a washroom, but drawing upon past experience and some degree of random speculation, we did reach some startling conclusions.
As you may well know, troughs are very difficult to manage within the realm of proper urinal etiquette, as they are not technically urinals. Therefore, we have decided, that whenever possible, troughs should be avoided. (i.e. always). There was simply found to be no justifiable reason to pee in such a locale, and we therefore cannot condone such activity. In fact, it is entirely easier to justify peeing in the sink, since they do after all look just like funny little urinals on a bench, than it is to justify trough use.