The DNC registry is a complete waste of time. There are a lot of "rules" on the books. That doesn't mean that they necessarily are enforced. I AM THE ENFORCER when it comes to my cell. I just don't answer phone calls that I do not want to answer. If they leave a voicemail and I don't want to talk to them, I don't. And, as you pointed out, some situations are not a violation, but it can still get pretty annoying.
Received this call at 8:30 at night. Pre-recorded message prompting to press "1" to speak with a medicare insurance agent to get the best possible price on Medicare plans. I only answered because I was pissed about a sales call at that time of night. And yes, I knew it was a sales call. I'm about to turn 65 and have been inundated with phone calls and mail related to Medicare, alert systems, knee braces and pain relief. The mail I can recycle. The phone calls have become a constant in my life. I've decided to answer them and disrupt their plans. I pressed "1" and the call was answered by an agent in Ft. Lauderdale Florida. I'm in Colorado, so it was 10:30 in Florida. Nice job. I played the game. Then I asked for his name and Colorado license number. He countered with "Why do you need that." "I need it because you are wanting me to be your customer." I was just being a good and informed customer. He hung up. This won't stop the unrelenting calls but I felt better for wasting his time.