Yes it is quite an entertaining picture! Until I read that article though I used to wonder how umpires could sit for so long in their chair, especially in four or five hour matches, without needing to 'go' or even have something to drink because they need hydration too in hot humid weather. That said I recall an ATP 250 match in the Far East some years ago when the umpire did come down between sets (it was a three setter) and help himself to a bottle of water and have a bit of a walk around to cool off.
Also in the days before bathroom breaks were allowed the only tennis I ever saw was Wimbledon, and used to wonder why during long matches some of the men used to occasionally sit with towels draped across their thighs between sets, until an Aussie player spilled the beans. They were too polite to wee on the sacred grass but they did use empty bottles!
Oh my goodness! ROFL! I