"Why was I detained?"
"I think you know. We went through your email records and found something quite suspicious. You've apparently been emailed several times by a wealthy sheik who is trying to get you to fund him in exchange for a financial windfall. Just who is this sheik, and why does he want to give you so much money? Is this some money laundering scheme? Are you affiliated with some terrorist ring?"
"What? That's just spam. I never even replied."
"Sure. A likely story. You could have sent your reply in code to any of these people you regularly email. Who's this one you labeled Mom? Is that your handler?"
"That's my mother!"
TBH, they probably already have all this information on most people. It's just getting people to do part of their job for them and volunteer part of the information, perhaps including some that they hadn't connected to them. Or just making sure that they get the right social media profile, rather than linking them to someone who happens to have the same name.
It's not like they could actually go through it all though. Likely it will just be fed through some algorithm, which will pop up whatever it's coded to pop up, and then they'll be harassed over something that's likely minor at best. It will be the same situation as the people getting denied an apartment to live in because an algorithm thinks they're a high risk tenant. Except this time, they'll be denied a job, because some second cousin bought an ice cream cone from a guy who's sister once dated someone who may have called someone who might have possibly been linked to a terrorist.