Hah, we've definitely thought about that possibility. Fortunately we do have a few things in place to prevent the most obvious abuse cases, but we need to get popular first!
I am thinking someone on Reddit posting a trick to save money on your sub.
On the roadmap are plans to target offers based on segmented customer data (lifetime value, etc.) so even if you did try to follow a trick posted on Reddit, it might not work for you!