We knew we could become a potential spam magnet. Like ive been mentioning in other comments here, we have an algorithm that does checks at multiple levels before a campaign is sent. If the algorithm deems the list as risky it triggers an automatic payment refund. The algorithm is also self learning. Over time its designed to assess the risk-function of an email list. (I'm from a data science background and SESS is a side project which uses learnings we get from elsewhere).