Funny you mention that, I once had a company track down and call my mother, who lived in another city. You can bet that the first thing she did was call me afterwards. It doomed my relationship with that company and I told people that story every chance I got, and not a single person wasn't shocked. When I heard the company went bankrupt a year later, probably because it couldn't hire any competent talent, I was relieved.

Contacting your parents and elementary school classmates is fine for an FBI background check as part of getting a top secret clearance. Key elements of that is they tell you in advance they are going to do so, get your permission, and what they find out is held in strict confidence by people trained to keep sensitive information secret. That's not at all the case with random employers calling up people they find you socially linked to.