Oh dear. I just ran across this on April's blog (thank you, April, for sharing this!!!). I find it rather alarming and I think you will, too.
Definitely part of making a house a home is making it a safe home!!!!
UPDATE: Mrs. Pear has kindly shared with me that Kwikset makes a "SmartKey" that helps protect against lock bumping. Thank you, Mrs. Pear, for sharing this!!!