I've been getting those notes from registrars for 5+ years (at least) - I treat them as spam. I've never had a registrar suspend a domain.
i.e. Just because it hasn't happened yet, doesn't mean it won't now.
The WAP emails you'll be receiving are something different, and you will be required to respond. If the email bounces, or if you don't confirm the email within 15 days, you risk your domain being suspended.
You can read the spec here: https://www.icann.org/resources/pages/approved-with-specs-20...
If you'd like to read the specification, it's here: https://www.icann.org/resources/pages/approved-with-specs-20...