It happens. I once had an eMail reported as spam for sending the recipient holiday greetings. Hard for it to be spam when there was nothing being advertised and also since we had exchanged holiday greetings in the past.
Too many people don't even know what spam is. If you signed up for it, it's not spam; you literally asked to receive it. If you don't want to receive it anymore, unsubscribe. The "report as spam" button is not an "unsubscribe" button. Too many people don't seem to grasp that very simple concept.
I have all my readers double opt in before signing up.
WARNING! Pet peeve time . . . 
Terms like "single opt-in" and "double opt-in" are not accurate. Anyone can submit an eMail on a website. You have no way of knowing the eMail account holder submitted it unless they confirm it. What marketers frequently call "double opt-in" is more accurately "confirmed opt-in."
If I start receiving eMails from a list
to which I did not subscribe, I don't care if there is an unsubscribe button. I am reporting it as spam. If someone entered my eMail address on a website for someone's list, I did not opt-in. So, if you do not confirm that I opted-in, your messages are going to be reported as spam.
So, what marketers may call "single opt-in" is more accurately described as unconfirmed opt-in. Maybe the eMail account holder opted-in. Maybe they didn't. You don't know. It's unconfirmed.
Thus, what's called "double opt-in" is confirmed opt-in. The eMail account holder has confirmed that they did opt-in.
In my opinion, using the term "double opt-in" perpetuates a notion that the process involves a needless repeated step or is somehow a hardship or problem. It is not. I have long been in favor of confirmed opt-in and here is why:
1) It is confirmation that the person did request to be on your mailing list. You don't want people on your list that don't actually want to be on it. Also, hard to argue "spam" when they confirmed that they wanted to be on your list.
2) Verifies that the recipient can receive your messages. If your eMail to request confirmation does not reach them, odds are other eMails might not either.
3) Provides some protection against spam complaints. Not foolproof, of course, but harder to argue that you're a spammer when you are actively ensuring people want to be on your list by having them confirm.
Often, when I see someone use the term "double opt-in", the first question on my mind is, are they from the Warrior Forum?
