The Nintendo 3DS can't use both StreetPass and SpotPass at the same time. If everyone's 3DS systems are connected to the Internet and downloading SpotPass data, StreetPass can't be used. While connected to a Nintendo Zone, the 3DS checks for SpotPass data periodically, which interferes with StreetPass. It's still possible to exchange StreetPass data, but the Nintendo Zone really slows it down. And if someone is downloading a lot of SpotPass data, like new videos in Nintendo Video, a bunch of Swapnotes, or even an old system update that they never got, they're going to be blocked from StreetPass for quite awhile. It depends on the range of the Nintendo Zone and all, but we've had mixed experiences with Nintendo Zones at StreetPass Arizona. Most of the time we'll get little to no StreetPass tags when in direct range of a Nintendo Zone. The convention in January was the worst. Normally at conventions we expect a few hundred or so StreetPass tags each day, and we had a lot of success at this same convention last year, but this year, because there was a Nintendo Zone, I only got about 100 or so StreetPass tags throughout the whole convention. This wasn't due to a lack of 3DS owners at the convention, because there were just as much as, if not more than, there were last year, and everyone was experiencing similar results.