I've never heard of a dedicated host that would /not/ allow you to send email. The terms of which they allow you to send mails will vary. Some providers will say no bulk email, some may allow bulk email as long as it is fully CAN-SPAM compliant, double opt-in, etc.
What it really boils down to is, how many complaints they receive about you. In general, providers are not going to monitor what you are doing, they only look at the complaints that people send them.
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