Does your favorite coffee shop have an Evil Twin?

I was at an IT ~~jolly~~ conference the other day, when one speaker got up and delivered a talk about cloned wi-fi hotspots or Evil Twins. Basically it is very easy to set up a fake wi-fi hot spot, have genuine punters logon to it and all you (as the hacker) would have to do is sit there and harvest their data, if those punters were gullible enough to use their credit cards over a wi-fi connection. (Or access any site that needed a username/password combo). OK so I may be a little late in coming across this exploit, but as the speaker explained, they [the security guys] had been asked by various law enforcement agencies to downplay the problem because (a) they did not want more hackers realising how easy it was to do and (b) there really isn’t an easy counter to the threat. Anyway and as Sergeant Phil Esterhaus used to say “lets be careful out there”