Sometimes we need to add people as invitees to a survey but do not wish them to receive an invite via email. Would it be possible to set up a dummy email address i.e. valid enough to be accepted by the system but not actually to a valid address so that anything gets delivered) so that opinio generates the ID and KEY data for this group of individuals for the survey. We can then extract this information and send the log-in details to these individuals via another method e.g. post
Seems like this should work. Create your "dummy" email address (either an internal address like "email@example.com" or at some free one such as Yahoo though they may view it as spam). In your invitation, as long as the name and e-mail combinations are unique (so they are not removed as duplicates) it should send all of the "dummy" e-mails to the one address. Another option that may also work that wouldn't actually send any e-mail would be to purposely make them all an invalid e-mail (so in the above example, don't create "firstname.lastname@example.org" but still use it for these people in the invitation. I would discuss this with your e-mail server administrator because there will be bounce-backs using this method.
I would think either of these may work. I know from our experience, Opinio will still send an e-mail even though the address may be incorrect - we know this because we know we have many invalid e-mail addresses.