Even if they had events anywhere near me (I think they probably only did them in London, and I'm closer to the capitals of Scotland, Wales, Ireland, and Northern Ireland than I am to London despite being in England), my parents would not have bought an accessory. So no. No events until Platinum, when we got wi-fi.
Hello there! I was able to attend an EON ticket event back in 2004 at my local Gamestation in the United Kingdom, where they were distributing the ticket. You had to connect your Game Boy Advance with a representative via a link cable. Once you had it, you could send out 100 EON tickets to people you battled or traded with. I believe my copy will still distribute them if I were to ever connect my game with someone else.
It was a fun day, I even received a goodie bag with some cool swag in there, and I met a friend who I still speak with to this day!