Am I the only Admin looking at blocking hotmail.com to stop SPAM? (edited)

EDIT NOTE: added details at end.

Half of the SPAM I get day in and day out is from a disposable Hotmail.com address.

They brag about SPAM protection for the USERS when you sign up for a hotmail account, but don’t do anything about stopping their accounts from causing a lot of the SPAM out there.

On a prefessional basis, would anyone use a hotmail account for work? If they do, then what is that saying about their company and they way they do business?

What do you think? Would blocking hotmail.com be a bad thing? I get closer and closer everyday.

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Running Domino on Linux, so any products that run on the server would have to work with this. Sorry, not a M$ shop.