Could be worse. More than once I've had these cards pushed through my door just because the meter reader couldn't be bothered to go to the side of my house where my outside meter is situated.
If you ignore that cards you then get a snotty letter from the utility concerned stating that under some Act of Parliament they can gain access to my premises.
If you ignore that letter, eventually the heavies turn up accompanied by an officer of the law, prepared to break the door down to read the meter.
Then is the time to make a response and tell them where the outside meter is located.
That happened to me shortly after I moved here. The house is fairly newly built and I believe that most, if not all new properties have outside meters so why did they show such a display of foolishness?