There's no such thing. The only way to avoid getting blocked is to make sure you send emails for legitimate reasons and that Hotmail knows that (which is dependent on your users.)
yeah, i dont think your going to find an expert about hotmail unless you can find someone who works for Microsoft....an i guess you wouldnt want an employee of them would you? lol.
As adam said, sent for legitimate reasons, because these companies will always find out.
You can also get blocked if you do not follow their rules and regulations – so in our opinion it is possible to get blocked even if you send emails for legitimate reasons (eg if you do not remove hard bounces from you lists)