Seriously, folks, why are we engaging with total strangers, uninvited, late at night, about personal views and private information?? There are many different ways to make money for charities and to spread the word about new research and it is a lot more credible than offering an opportunity to a cold caller who could be ANYBODY. As long as we reinforce this, the more knocks on the door late at night. A 'breast cancer jacket' and 'ID' [would you REALLY know if it was genuine or not?] should not give you access to someone's home or life.