I'm sending the emails only in Florida. Even with a custom domain and the supposed "right" email settings, I did find that a large percentage end up in the spam folder. At the same time, I have seen some positive response as well. But then I received a threatening email from Squarespace (I use them for email campaigns), and so I wanted to be sure I at least wasn't violating any laws.
"Don't use our Services to send spam, emails that violate CAN-SPAM or other laws, emails to people who have not explicitly consented (where such consent is required) or other unsolicited communications (bulk or otherwise), promotions or advertisements. Note, we reserve the right to determine what constitutes spam."
As far as I know, there's a difference between cold marketing and spam, but I have a feeling a lot of recipients are marking it as spam and, like you said, it could be doing more harm than good.