I got a doubt only when they were going back I saw thru my balcony door , that they didn't go to any other home in my street and there were no vehicle with them. They walked till the end of the street and turned. I was googling a lot of nest thermostat deals and RFD forums for past couple of days. I downloaded a home Depot instant rebate coupon from Enbridge site. May be because of that download, they got to know that I'm looking for a smart thermostat and came to my home. Don't know.
Whatever be the reason, I will not open or answer unknown ppl at the door. New home owner, was not aware of door to door scams like these.