I don't know...I gave up checking. I do however buy them from my local Best Buy. Hell, one of the gamestops by my house doesn't even sell them. I was very surprised when I tried to buy one from them and the guy was like, "Yeah we got those." *Hands me Wii points card* He then went on to tell me that they work with the 3ds....it was quite entertaining.
We must learn to live together as brothers or perish together as fools. i5 2500k | GA z68xp-ud3p | 8 gigs 1600 | GTX 570 SC | 750w Corsair | Asus VS248H-P
They don't work, but Nintendo should be a lot more clear that they don't. I don't think the assistant was trying to trick you, he probably genuinely assumed they would work.
I know that some stores selling the points cards to customers have done the same thing without realising because it's not clearly stated anywhere. After all, the system is called the 3DS, marketed the same way as a DS and has the same library as the DSi has for it's online store. It's easy to make the mistake.
Gaming systems: PC, Ps2, Ps3, Gamecube, DS Lite, Xbox 360, Nintendo 64 and a Dreamcast