Davis and Sprillia Spinnererett were trying to have what should have been a rather private conversation between them in a very public place. Even if he made the Nuro Net go dark for a while in the immediate surrounding area to encourage others to leave, they say walls have ears and doors eyes for a reason. Reporters were also damn good in the hyper-digital age.
Cameras and listening devices that had internal data storage were tiny and could be easily hidden in something the size of a cathedral. Even the best security sweeps might miss one or two, and people also had their own eyes and ears.