Once mrsOpusman and I were on NZ ADL-AKL, back when they still had a proper business class. We were the only pax in J. Sometime after the meal service the hostie came up and very politely asked if we would mind if some pax from Y came up to use "our" toilet as there was only one working down the back and there was a rather large queue. Of course we said "yes" and the hostie then spent the next 20 minutes or so guarding the curtain, letting one pax up through our sacred space at a time. And then they gave us some airpoints vouchers to say thank you!