We all know that the situation isn't optimal, but you shouldn't be so afraid. It doesn't change anything for your event, playing and chatting works as usual with the unsecure connection. You should be fine as long as all participants are connecting from home.
Those who have to take especially care are people connecting from school, workplace, restaurant, train/bus/tram station, and other public or shared networks. They should already know it anyway.
All those who stay at home, using directly the internet connection provided by their ISP, are pretty safe even with the unsecure connection.
Note that the secure connection still works with the web client as before if you are connecting to qcsalon.net via HTTPS. Only windows client is affected. If you are still afraid, this might be an option for you.
One thing is sure though, secure connection won't be back on the windows client by wednesday. Secure connection won't ever be back in version 2.2.8. It will only be available in the new 3.0 beta.
With the hope that this post clarifies the situation and helps putting your mind at rest.