You guys aren't listening, and don't seem to care about testing.
Logging out does not kick u from the raid, i've tried and tested, and confirmed that it doesn't.
The trick is to start logging on the pull, so u enter combat 10seconds from logging out, and you'll be placed on the threat table.
If you miss the logout on the pull and get into combat, u can just kill yourself and it'll let u logout when your dead, or hard reset wow, and log your other character.