If Daro was Illuminated he'd be able to get past the examiners, but he wouldn't ping on Sense Chaos, which might be more fun in the scenario. But... what if his Priest was Illuminated? The implications undermine social certainties. Is this an isolated incident or is there more to it? Does the Priest become a future enemy, or is this a trial-run of a Lunar plot to infiltrate non-Chaos cults? Will the players ever be able to answer these questions, or just be left feeling unsettled and paranoid?
On the original question - chaos-tainted infiltrators of urban centres need only to stay 15m away from Uroxi. In New Pavis, quite a few neighbourhoods would be unlikely to welcome Storm Bullies. Downtown, Suntown and Rich Hill could offer a fairly safe base.
A city ruler might be able to muster a group of SBs to use their talent, but good luck persuading the whole population to submit to testing. At best, you could vet small groups, like your personal guard, or prominent individuals - so chaos-tainted individuals would do well to keep a low profile and act through minions. More chaotic chaotics can just rely on dumb luck.
There's a question of prevalence here. How often does Sense Chaos ping? Uroxi will avoid places where they sense chaos so often that they can't find or fight all of it. Do Storm Bulls avoid cities where they've lost the fight?
