I shouldn't have said they "need" to. More like it would be very much appreciated if they did. I've made sure to keep track of that now, but I think they could do a little more to help people, who haven't learned from making the mistake yet, avoid losing their domains.
Funny thing is that I had a domain with a different registrar about 9 years ago and I couldn't get them to stop mailing me expiration reminders. They kept coming well after I intentionally let the domain expire.