The problem exists in America as well; my elderly father was hit by it. Luckily my mom overheard his end of the conversation and put a stop to it. (Turns out, the scammer is very good at crying, but not very good at proving their alleged identity by knowing my mother's name. Hurray impromptu two-factor authentication!)
But I believe that it's illegal to operate cell phone jammers, unless you're the government. And for good reason; it's wonderful that you prevent someone from being scammed, but if I'm attacked by a mugger near an ATM, I'd rather like to call 911.
The initiatives in Japan were in cooperation with the police, so I'm sure it's not impossible for them to get the proper permits. And many Japanese ATMs already have a "panic button", I'm sure the ones in question would too. Mugging isn't a huge crime here so I guess that's more of a problem implementing it in the US....
But I believe that it's illegal to operate cell phone jammers, unless you're the government. And for good reason; it's wonderful that you prevent someone from being scammed, but if I'm attacked by a mugger near an ATM, I'd rather like to call 911.