[res0nat0r]

I'd say investigating corporate trade secret leaks with substantial evidence pointing to an MS owned Hotmail account, to which the leaker agreed could be accessed by MS personnel would be deemed necessary.

[nikster]

I don't think the reason is relevant at all. Just because XY says there's probable cause doesn't make it so. That's why we have the judiciary system.

Microsoft has no legal authority to make that call.

[res0nat0r]

They do...it is in the TOS you agree to when you signup to use Hotmail.