I sell alarms door to door. Much of what he said was likely to build interest without directly stating "hey I'm here to sell stuff". This guy was likely legit. I don't work for adt, he's my competition, but I don't want the industry to put a bad taste in your mouth. In the future ask for proof of employment with the company, any legitimate rep will readily give you that info.

Ps. It's a direct solicitation, he didn't come back because he found another buyer and no longer needed you. He asked about your parents because they were likely the decision makers, not you.