If I'm reading this right, the registrar suspended the domain because the contact details weren't validated by the customer. It wasn't ICANN.

It seems to be up to the registrar -- other registrars I use send an email that requires no action if the details are correct. But one I used previously suspended a domain of ours because the guy that registered it ignored the email.

I don't know about ICANN, but I have had domains suspended for not confirming email addresses on file in the WHOIS on a yearly basis.

Yes. Especially when it's manually reported.

https://forms.icann.org/en/resources/compliance/complaints/w...

Many times.