Dear Anonymous "Name",

How do you check the email address is valid if you don't email it?

https://www.ripe.net/participate/policies/proposals/2017-02

I think the NCC will be able to tell more details when the plans are ready. For now, the relevant part is probably:

The RIPE NCC will validate the technical parameters of an “abuse-mailbox:” attribute, such as syntax, domain and mail server configuration, to determine if it is correctly configured to receive messages.

One can determine with a high degree of confidence whether mail sent to a given address is accepted for delivery by the mail server specified as MX in the DNS for the given e-mail address. To me it is a good start and much more than not checking anything. One can probably not test whether the accepted mail is indeed delivered and even less whether is is eventually read by a human. The latter cannot be checked even if one does send the e-mail and even get a reply (generally speaking one cannot be certain the response was sent by a human). Therefore, I would leave the details to the NCC for now. Best regards, Janos