Might sound stupid but they must feel the urge to number 1 or 2 when out racing or climbing and have never seen anyone use a portaloo climbing the Alps!!!
You forgot to add all the journos, photographers, police/ambulance, motorcyclists, team/support/race-management car drivers and very assorted passengers, caravan people? One portaloo may not be sufficient?
Or, of course, one gets used to managing one's bodily functions.

A scatological contribution from someone who is proud NEVER to have used a toilet on an Egyption State Railway service in five years, despite .... well, let's not go there
