Simplex Push button door locks can be defeated by a magnet
 

http://www.nytimes.com/2011/03/27/us...ef=todayspaper

"Mr. Miller also argued in court that the magnet was unwieldy and too
powerful for most people to use. "It's a big, heavy thing that if you have
it in your pocket, and you happen to walk by something that's made out of
metal, you will get stuck to it and have to call 911 to get your pants
somehow removed to save yourself," he said.
This month, lawyers for the plaintiffs showed a video in court as an
informal briefing for the judge that countered some of Mr. Miller's
contentions. The video shows someone sliding a magnet against a lock and
removing it with one hand. The magnet pulls a locking plate away from the
mechanism, allowing the door handle or knob to turn freely. Once the magnet
has been removed, the narrator says, the plate slides back into place, and
there is no evidence that the mechanism has been bypassed."

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Bobby G.