Yes it can hurt reputation and torpedo open rates if a sender receives consistent spam complaints over a sustained period of time. I’ve seen it happen in real time with a client who claimed their leads were warm/opt-in when in fact they were not all. Open rates went from 38-40% to under 7% within a few hours. So the spam button is effective, that’s why it’s important to only email warm/opt-in contacts for bulk email, send engaging content and make it easy to unsubscribe.