There might come a time when someone needs to have plausible deniability, or to protect their location, and life. Domestic abuse victims, journalists, and whistle blowers are examples of such populations. With that said, Ka-Tel will issue a 90z telephone to the person for as long as they will need the number. The number will have its own voicemail, and Caller ID information will be Undisclosed Caller. This is opposed to Anonymous which is for people that block their number. The person will obviously have to pay for the line, but only Ka-Tel, the national government, and person the number was issued to will know who the number belongs to.
This is not for witness protection. Witness protection will receive a new GIN, and a new NIN. With that said, their old numbers will be recycled months or years down the road. You would receive your new numbers, and use those new numbers for services. Private numbers are intended for people that need to keep their current life, but are in possible danger due to their line of work, or domestic situation. Once the number s no longer needed, the number will be relinquished.
Unlike your normal number, a private number has nothing to do with your NIN, and you would only receive 1 private number. There is simply no way, nor a need to provide multiple private numbers to a single person no matter how risky their life is.