RainKing is not an opt-in database, consent has not been obtained for third-parties to contact anybody in our system as it is an impossibility for us to obtain opt-ins from hundreds of thousands of contacts on behalf of our thousands of clients. Internally, we are compliant with EU-US Privacy Shield regulations and we were compliant with Safe Harbour prior to its replacement by Privacy Shield.
It is the responsibility of our clients to follow the local privacy laws that are in place according to the regions into which they are marketing, meaning that an opt-in is required in order to email many European, APAC, and Latam countries as well as Canada. In the US, you are free to use any and all of the information without restriction, as long as you obey CAN-SPAM regulations (i.e. include an opt-out link on any mass email campaign).
In our role as a data controller we surface our information in a transparent and ethical manner, and if any of our contacts call or email in and ask to be removed from our system, we comply (even though we are under no real obligation to do so).