I'm pretty tech savvy, but if any company sends me umwanted emails that don't have an unsubscribe link at the bottom which I can access without logging in, I ma

I'm pretty tech savvy, but if any company sends me umwanted emails that don't have an unsubscribe link at the bottom which I can access without logging in, I mark it as spam, because that's what it is. If enough people do this, Gmail learns and applies the filter accordingly soon enough.