I have a website where I send out surveys to people who want to take these surveys. They gave me their email address, so they do want to take the survey.
The problem is, our server had malicious code injected into a contact form and that resulted in a blacklisting problems. The blacklisting seems to be resolved, but now I'm trying to do everything I can to help make my emails look cleaner and not spammy. I'm using PHPMailer to send with SMTP authentication.
One important tip I've come across is to include an unsubscribe link. But these people aren't actually "subscribed." They will only be emailed to do a survey one time. So I was wondering if I put a link that leads them to a page explaining why they received the survey (basically remind them they game me their email) and just name it unsubscribe.php? Then I will name the link "click here to unsubscribe." Would that be sufficient?
You can't just send people random stuff because you got their email address. You need to have explicit consent to send them things for a specific purpose, and what's more, you need to be able to prove that they gave that consent. Such a record of consent effectively is a subscription, so an address obtained legitimately would never raise this question.
If they did give you their address willingly, but you have no record or evidence, it's legally indistinguishable from you having harvested it from a random web page.
To put it another way - if you don't have this provable consent, you can't legally send them anything.