When I post a draft to my MT server with a future date, I get an error message from WLW (RC). It's the same message I would get if I published with a future date.
If I tried to publish with a future date, it would really be an error, and the message would be correct. But posting a draft with a future date and then changing the status to Future on the site is the most efficient way I have of publishing for a specific time.
At present, I could turn the message off, but it would apply to both cases.
Sorry, but I don't think there is a way around that at this time.
It would be possible to turn off the error, and then write a Windows Live Writer pre publish plugin that would warn you for real publishes but not for drafts. The documenation for writing a pre publish plugin is here: http://writerdevzone.spaces.live.com/blog/cns!FF912D98C958E9D3!170.entry-Brandon Turner [MSFT]