Copyright would be a problem, although being a very small niche magazines ensures that they do not have that much money to sue you and will warn you first.
The real problem is that you should keep this solution for yourself, because writing here about it ensures that there will be many BH marketers, who start abusing such method which WILL devalue it. So if it works for you and you'd like to keep it that way for a long time, take this post down.