As many have noticed TSW3 never left Game Pass on the 1st despite DTG repeatedly saying it would. Microsoft have now published their list of comings and goings on Game Pass for the first half of September, Train Sim World 3 leaves on the 15th. https://news.xbox.com/en-us/2023/09/05/game-pass-september-2023-wave-1-announce/
We all agree that having the exact date is the best possible option. But, if in doubt, I think it is better that DTG tells you that it will leave Sept 1st and have it actually leave Sept 16th than the other way around.
DTG: "Yo, Microsoft, we want TSW3 out of Gamepass on Sept 1st" MSFT: "Yo, there's a mandatory 2 weeks notice. So, how does Sept 15th sound?" DTG: "Yeah, OK"
Or... "What? Are you guys still around? Yeah whatever you want. We already have a bunch of low scoring games on GamePass already. No use having this one around"