I think the whole point of the events are meant to be for people to work together as a server.
However you cant make people do it if they don't want to.
That's why a opt in option would be better and then the rest of us wont have to struggle to pick up the slack of none participating active server members. then maybe the % would be only representative of those who opted in to do the event and would be more achievable.
Which would also mean that only them players would get rewards which would also be more fair rather than sitting back doing nothing let others do all the hard work/or just try to profiteer of others trying to get the rewards for everyone. As at the minute everyone gets rewards whether they participate or not which can also put people off even trying as they get the free ride anyhow.
However after being so close on the EOW event to getting the 100% i am so proud that all 3 UK servers have at least 100% and I am going all the way to the end making and donating balloons good luck everyone