Email marketing is getting harder and harder all the time.
As a sponsor, we are very aware of the risks of spamming and we do everything we can to prevent and avoid it. But as you point out, it is very difficult to keep everybody happy. We occasionalyy even get a spam complaint on our own legitimate opt-in email lists. People forget they signed up, or for whatever reason they decide they don’t want to be on a list any more, and all of a sudden you are accused of being a “spammer.”
I hate to be negative, but I’m starting to get the feeling that email marketing may be virtually eliminated in a couple of years if the ISP’s and government agencies can’t figure out a way to shut down the true spammers.
If the majority of your business comes from email marketing today, I strongly encourage you to disverisfy so that you are not left out in the cold if and when the hammer comes down on email marketing.