Well that was awefully quick, although I did expect someone to crack it within the first weeks. If it's a physical change-around for the DSi, it should be fairly easy, since why would the big N change the other components inside the DSi? (Compared to the DSlite)
I suppose they might be doing firmware updates to stop this, however, if they do it like they had it with the Wii, then you could just stick to one version. Big problem for the firmware updating however. Wii uses the net as one of the more main features, (and not sure about game compatability, but happens with other consoles), whereas the DS apparently does not (or, the DSi is changed much more than that,) hence making anyone without WiFi access unable to update their fw and hence play newer games. Also note that the official N WiFi adapter was discontinued, so where's the logic behind using WiFi to send out bricking? Sure, you could use your router, but that would mean you'd need access, and yet again, it's the gamers age for DS's that might change what happens.