Inala didn't blindly target Safara. He first observed the type of customers that entered her restaurant. Most of them were high-profile people, ranging from bureaucrats to even nobility.
If the people frequenting her establishment were people of such calibre, then sensitive information ought to circulate there, especially since the restaurant also promised them other activities, from alcohol to casual gambling.
Safara's powers were also geared towards making her target relax. And if someone is relaxed, and starts downing alcohol and are having an enjoyable time, they are bound to blurt out a bunch of state secrets.
She was perfectly sneaky about everything, intending to use such secrets as leverage to strengthen her influence. Therefore, her customers didn't seem aware of it. Maybe they were aware and didn't seem to mind. That part wasn't exactly clear.
