A tech company source used to make me turn off my phone before meetings because of concern that his employer would check to see if our phones were near each other. This was not a crazy concern it turns out! TikTok tried something like this to hunt down leakers: https://www.nytimes.com/2022/12/22/technology/byte-dance-tik-tok-internal-investigation.html
ByteDance Inquiry Finds Employees Obtained User Data of 2 Journalists

The company’s internal investigation showed that workers also obtained data on a small number of other U.S. users.

The New York Times

@kashhill

I wonder if there is still a market for those old analog voice activated tape recorders that could fit in your pocket. Its not as snazzy as smart phone recording but unless they frisk you, you can hand over your phone and still get the 'dirt' or whatever.

Down side you would have to wire yourself up like some 70's mob movie.