This reminds me the story of a pressure cooker and the backpack - https://www.forbes.com/sites/kashmirhill/2013/08/01/employer-reported-suspicious-google-searches-that-led-to-terrorism-task-force-visit-for-long-island-family/ It's a 10 year old story and back then it seamed like a bad dream. Turned out it's a bad dream we are living today.

On top of that I do remember reading about people getting a complimentary police visit just because they have ordered nitrite based manure (mostly farmers). Unfortunately I don't have a link. And I do remember reading about students questioned by a police based on a library renting habits. Back then, when I was like "this will kill the privacy as we know it", I was ridiculed.