Update: I got the E-Mail. It comes from Ticketmaster. And its per ticket (if you purchased 2 tickets, you can get 2 albums), so I'm getting 2 CDs. I could give one as a gift.
And yes, they do this because it counts as a sale for Billboard for each album redeemed. Lots of artists do it now. Since people are less likely to buy music nowadays, its a good way to get people new music and get strong sales for at least the first week of the charts. Normally Billboard doesn't count free albums, but this isn't technically free since you're paying way more for tickets than is the cost of an album,