Comments:

The question has not been addressed as to whether opt-outs must include all databases within the company. Ex. there may be same emails in different department areas. I could not find this aspect in the rules. Also, if someone has published their email on a web-site or in a directory doesn't this invite email solicitation until they opt out? Also, a transactional relationship should be able to include offers on other products. As far as forwarding goes, I think it is the responsibility of the forwarder to forward the entire message with the opt out - and if this is not done, the original sender is not liable. The forwarder would most likely have a relationship with the forwardee, so this excludes the sender from having to have a relationship since it is indirect. The original sender should still be required to have an opt out.