Verisign is notorious for doing that - also for charging excessive prices.
But if you get a notice from WDRP (wdrp@name-services.com) asking to validate your whois info, it's valid.
According to the ICANN rules, your whois info has to be validated annually. If they can't contact you/you don't confirm the whois, your registration can be canceled.
Had a couple of clients loose their domains because they had old, no longer used, email address in the whois so their info couldn't be validated. Recovered one of the domains, but lost the other one.