I get that you probably added it somewhere in the giveaway text, but from a post somewhere, it was indicated the giveaways were more to garner attention, not as a profit-making venture. It turned me off completely when I started getting those. It gave me a negative impression on both Scott's Cheap Flights and on any companies that started sending me cold emails.
Maybe you can be more selective in your partners, or perhaps work with the partners in what gets sent out. I'm very judicious in what I let get my attention, and seeing these kinds of random sales pitches with no actual value proposition was annoying.
I went back to the giveaway and found the e-mail consent in the tiny text under the consent checkmark for signing up, so I can give you that for having the warning there now. It was not noticed when I signed up, however.