As long as these tournaments start by a timer there will be these issues. The simple solution is to give control of the tournament to the tournament creator. Instead of the event starting by a timer, it would be better if the creator had a "start" button, and every other player hit "accept" just like we do when creating regular tables.
This way, when it's time to start the tournament but you are a player short, you can wait a minute until you get another player. This is only for real time tournaments, as turn based does not require everyone to be ready to start at the same time.
I have played in about a dozen swiss tournaments for 6 nimmt. Really about 30 if you count all the times we all abandoned all the rounds of the tournament for 1/2 hour while trying to create a new tournament and get everyone signed in at the perfect moment...and then 1 player was 10 seconds late again....wish we had some control.