Quite the opposite IMHO, understanding that the anticipated means of
communication will be email and that the email address of a probe's host
will be generic, eg. <ripe-atlas-probe-[number]@atlas.ripe.net>,
redirecting all incoming emails to a final address. The redirection
would be configured via the portal then.
Using an address as described above would allow enumeration attacks.
If it would use a hash instead it would be safer.
The hash for probe XXX would be obtainable via the portal, where you
would need to look up probe's details anyway.
Geert Jan