I mistakenly used my card at a Mickey-D's that I had been warned about. It was late, the kids were bitchy hungry. I stopped. And I paid. It only takes someone about ten seconds to get all of the information they need, (with their own swiper, and seeing your security code.)
Also, trolling neighborhoods for Wireless networks with lax security settings is big business, even with all the warnings out there.
I have all of my cards set to use a code, or pin, or something if they are swiped outside of the area I normally operate. Having to enter four digits is no problem for me, at having the convenience of when (not if) my card is breached, it is put on a cut off list the first time it is used without the back-up code.
Other than the one time I had them make a run at my card, all across the South, I have been called twice and told I am being issued a new card. Like I said, it is now caught for my card(s) on the first try.
Good Luck!