I went to a festival a couple of weeks ago and I think they may have cracked it: a bank of female portaloos, a bank of unisex portaloos and behind them, a big urinal area. I stuck to the female ones to start but as the night wore on the lines got longer so I ventured into a unisex one and it was ok. Probably because most of the persons most likely to piss all over the seat/floor were skipping the lines and going straight to the urinal area. Could this not be replicated in indoor loos as well, the option of female, unisex and urinals? And then we could all be happy? Couldn't we?