Wait, what counts as an event? Wi-fi distribution? Gamestop? VGC tournament?
Well, you shouldn't have to leave your state or province just to get some stupid Pokémon. I'd be fine with Wi-fi or store distribution.
I'd say anything you can only get for a limited time, or have to go to a specific location to get, or both. It's like a Mario game having secret levels, but locking them away until they release them later as special events or something, but you have to go to a Mario movie and download it there for a limited time or else never have access to it ever. (On a slightly related note, **** you e-Reader) --- "The best things in life must be taken... by force!" ~Captain Khan