That's what autodrafting is for, not joking.
We will never know what we'll do on a specific day, at a specific time 2 weeks from now. For all we know, we might not even be alive then.
The point is, unless someone has an already existing conflict, we count that day and time as "free" and we go ahead and agree on it. If someone can't make it for whatever reason, then auto-drafting will be the name of the game.
Gotta make a compromise one way or the other, otherwise we'll never synch the plans of 10 people living on 3 may be more continents.