Five days into the 3DS’ North American release and already the StreetPass feature has thwarted the cheating ways of one husband in Los Angeles.

“I suspected that my husband was cheating on me because he would always text on his phone, and when I’d ask him to see it, he had to erase whatever conversation he was having before he gave it to me.” Without wanting to hire a private investigator to snoop around or install cameras, Karen got the idea of using StreetPass in 3DS.

“I read online that the 3DS was going to have this StreetPass function, and it would allow your system to hook up to another person’s system. So I secretly bought one.”

Karen said that her husband, Jeff, is a hardcore gamer and got a 3DS at launch. She decided to “go out on a limb”: If the woman he’s cheating with does exist and comes over to the house, she would probably have a 3DS with her.

“I saw his receipt and noticed that the bill was $548. … I thought that sounded like the exact price of two 3DSes, and since one definitely wasn’t for me, surely he got it for his mistress.”

Karen’s plan was to just leave her 3DS that she secretly bought in her closet and allow the StreetPass to do its trick while she was at work.

“I came home from work yesterday and saw nothing, but on April 1st, my 3DS’ StreetPass was lit up and saw the bitch’s Mii on it.”

The moral of the story is: Don’t cheat! I say good job to Nintendo for inadvertently creating a clever anti-infidelity device that no one would ever suspect.