First...I've never seen an actual game/event thread where all the host asked if people would post that they are tentative or sad that they can't make it. They only care about who is coming.
- I have read and fully understood the rule/expectations/conditions/etc of the game thread. No matter what I think/feel/historically may have done...what's in the game thread's post is what it is. And I agree with it for the event.
- I will be there, on time, ready to go
- I am prepared (physically, kit/gun/whatever is required) to be a fully committed participant for the entire event.
No more complicated than that.
"flaking"...I take it to mean posting "In" and then not showing up...no reason, no explanation. Posting "In" and then having to post "Out" later on...that happens.
Since with very few exceptions EVERYONE should have an idea of what's going on for the next 5-7 days of their life...and since planning a day in your life out as much as 2 weeks in advance isn't impossible...posting "In" or "Out" should be a pretty firm thing that can be made well before game day. In every day life...if you can't sort your life out for the next couple of days and if you can't do a bit of planning around a date in the future...then you are a flake. Some people are habitual flakes and don't have it in them...it's just that it doesn't work very well for any structured game where other people end up depending on participation of others.
If you don't like that/can't do it...then just stick to the skirmish pick-up open to whomever shows up don't care games. (see first point)
Memel/Boche is bang on too. Players who have their head straight on committing to being "In" are fully expecting in return from the host that the game is on & as described. They're pretty pissed if the host flakes. (I think that happened out east once where the host neglected to tell all the guys signed up that the game was canceled....don't think it went over well).
If you're going to host some complicated "might be this day or the next you're committing to playing one and then if that doesn't happen you've already committed to being there for the next date so don't don't flake on that other date either or you're going to be added to our not welcome list"...well to each their own, but I can't see too many people with actual other things to do being able to commit to that.