Beware: if a young adult knocks on your door, claims to be a neighbor or local resident, and suggests that they are selling magazines to win points for a trip to London, you should suspect a scam. I just experienced this, with the youth claiming to be a member of the San Jose State University women's Club Soccer team (that have none) and mis-pronouncing one of the cross-streets in the area in an effort to convince me that she was a neighbor.
Don't be fooled!
Ask to see a receipt before you write a check or hand over cash (which she offered to accept!) - if you see Elite Circulation Inc. with an address of 508 W. Mission Ave., Suite 204, Escondido, CA 92025 printed on the receipt, or South Coast Circulation, Inc. printed on it, just politely refuse and close the door.
Here is a link to similar scams, which are now taking place in California:
Soccer, Neighbors, Magazine Sales, All Lies
The Federal Government has advice and a list of resources as well.