I completely understand your position. I'm all for a consistent, secure system--that benefits everyone. However, there should be a limited amount of room for flexibility in certain situations. For example, if someone wants a voipo line as a secondary line (a per-minute plan or limited plan like 500 min/mo), they might want to pass the CID info of their main number. This would be my situation. Another good reason to pass a different CID number is during a number port--if I sign up for voipo and want to port my number, it would be nice to use the voipo line for incoming by forwarding the existing line to the voipo# AND outgoing, provided voipo can pass the ported number, even though it still operates using the temporary number.

I'd be interested to hear from other users what kind of limitations you think are reasonable. Should there be just one additional "authorized CID"? Should there be up to 5? Should there be a monthly fee to "buy" more authorized CID's beyond the standard limit? From a security standpoint, should these numbers be verified somehow? (I envision an automated verification, where upon entering the number in vpanel, voipo calls that number and asks for permission, and if given, a numeric passcode that is displayed on the vPanel screen when submitting the number. Refreshing the screen would show status--Active, Denied, or Invalid Passcode.)

In terms of people sending invalid CIDs, can't you figure out who's making the call based on registration info? I'd think you could send CID based on the registration, couldn't you? (FWIW, I have another provider with an alpha (non-numeric) SIP username, and the CID sent from that account is the assigned DID number...)