You don't choose to leave tracking on, it's on all the time. If I were unethical, I could call a phone number, give them your phone number, fax a fake "exigent letter", and the wireless company would give me the latest pings from your phone. No warrant necessary. And they store all this data essentially forever, so if they want to dig up something to pin on you, they just sift through your metadata until they find something they can work with. Maybe you unwittingly parked near a drug house, or used the same wifi connection as some criminal. Just get the criminal to say they were conducting a transaction with you, in exchange for leniency, and you're toast, unless you have hundreds of thousands of dollars to hire a competent attorney.
And no, I would never do a DNA test, especially the inexpensive ones that supposedly show you your heritage. Legit DNA sequencing is expensive, and almost all of these services are very inaccurate. Think of them as genetic horoscopes. They're cheap because the test isn't the product they're selling, it's your genetic data that makes them money. These companies are owned by nice corporations like Blackrock (Ancestry.com). Mice die in traps because they think the cheese is free.