We had the ADT guys visit and were impressed with their politeness and knowledge. We had invited them to come back to our home at 18:30 as we had been meaning to get a security system for some time. A friend was recently burgled and then bought her security system where as we thought we should get ours installed before we get burgled. Unfortunately a fact of life living in London these days. If you don't have a security system you do open yourself up to attack and the ADT people are likely to be able to give you such figures if you require them. Obviously everyone's experience is different but at the end of the day these people are doing their job. It's not a job that I would like and they deserve a bit of human decency. If you aren't interested then say so and don't let them in. If you aren't interest and don't already have a security system then more fool you. We had a call from the manager (standard practice) the day after the visit to make sure nothing untoward had happened so they take bad sales behaviour seriously.