I've merged the thread about the Member's Card created by extinct with the Events Discussion thread~
Now onto the Event:
For the length of time it has taken the Member's Card to be released, I'd be surprised if it was not done for Europe too. It would actually make more sense for them to do it together, seeing as US Platinum games can access European Wi-Fi Events, as tested with my own US version of Platinum when the Secret Key was released for Europe. To break continent barriers, I could also access the Jirachi Event in Japan with my Japanese Platinum, so its likely this Event will be the same.
I can't access PokemonPlatinum.com, (for some reason, the site won't load... -.-;; ) but I can venture to guess there has been no Regional Limitations set in the wording. It doesn't even specify on Pokemon.com where it is being released, so it may be a safe assumption that both the US and Europe will get it at the same time.