that's true but the real problem is that ( as far as i know ) the DS is not meant to work over hotspots without beeing hacked. and i don't assume nintendo would like to provide something to force people to 'hack' their stuff.
Thats..not true at all. The DS can use any WiFi hotspot as long as its unprotected/protected with WEP, and doesnt use an html style login. It also has to be 802.11b, which most hotspots now-a-days are both 802.11b/g compliant.
Thats not the problem, the problem is finding and obtaining access to hotspots. Sure you can use the one in your house, but that ruins portability. You usually have to pay elsewhere for WiFi access, or at least buy something from the store (IE, Starbucks, McDonalds) in order to use the internet. The unavailability everywhere, and the price of WiFi hotspots kill this idea more than anything else.