This can be a hassle, but the main point is that you don't need to stay 3 hours in-game, the events will become available 10 minutes before the next hour, just be there at least 5 minutes earlier and do 3 rounds of the live event. YOU NEED TO COMPLETE ALL THE ROUNDS 3 TIMES IN TOTAL, which means that if you are playing and there's little crowd to do the event, skip it and wait for a proper time, if you do 2 rounds with 3 events each and the last round you complete only 2 this won't work, for example, so complete all rounds 3 times in a row.