I may be out of line here, but what the hey….
Pleeeeeease……the management of Strata Schemes is difficult enough to handle in a fair, sensible, and legally compliant way without this incessant researching and quoting of legal precedents in response to straight-forward questions.
OK this one’s a bit tricky, but thankfully it doesn’t involve contract law or the High Court but rather the common sense approach that was alluded to by Scotty (post #2) and reinforced by Austman (post #3); the resident who contacted the plumber could not reasonably have been expected to know the source of the water leakage, so logically they contacted the O/C’s plumber who located that source within Nathan’s Unit, so he should pay the plumber’s invoice.