If you advertise/promote your own domain, then they cannot dictate how you drive traffic to your own site. The only exception might be if your domain just redirects to the offer because that's basically equivalent to direct linking to the offer. However, if you promote your own site that has a landing page with a link to the offer or a banner (assuming that text links or banners are allowed), then I don't see how they could prohibit you from using offline sources to drive traffic to your own landing page(s). If it's an email-only offer, you could advertise the URL to your squeeze page and send people to the offer via email after they opt-in. As long as you're staying within the promotional guidelines for the offer, I don't think that using offline advertising is an issue.