I've been told it's pretty easy to do so at Comic Con and similar conventions. People always have their 3DS out to clear Streetpasses. I wouldn't call the cap a problem per se, but it's bizarre to even have a cap on it. I think the most I've had was five or six when I was hanging out at my friend's store. I suppose the idea is to keep people constantly using the software and if you StreetPass someone more than once, it counts though I actually think it would be kind of funny if you had two or more Streetpasses with the same person that their Mii just walks/bounces to the back of the line and says, "Oh, nice to see you again."