There is I believe another scam that is not well known until just now!
I noticed some time ago that the outside gas meter boxes had been opened more than once over a short period of time,one which had a faulty catch so hard to close quickly.
What is I think happening is like with the locksmiths one to see if sticker removed or messing with doorbell to see if repaired is to take reading of gas meter. then come back a day or so later to see if has changed a lot. If not, further return and read will tell them no one in the house in cold weather as heating was not being used.
Probably no one living there or away..... Do something so you can easily tell if cover has been opened without having to touch box.......