If I may, there are other aspects. The social insurance number is used for obtaining various benefits. In all of the benefit programs that Service Canada administers--and likely all other provincial departments--it would quickly come to the fore if tax was being deducted for an individual many times simultaneously. The CRA would pick that up and inform us immediately, and our investigation would commence.
Canada Pension Plan premiums are deducted and recorded by us, remitted to us, based on a social insurance number, so if there were four people working on the same social insurance number, we would be getting a lot of premiums, and immediately the flags would go up in the computer systems of the Canada Pension Plan, similarly with the Quebec Pension Plan, and so on.
We do match our benefit files with the CRA files, and we match with employment insurance files and the premiums there. If there were multiple people working on the same social insurance number, we would immediately notice an anomaly coming up. In these matches, we send the observations to our investigators across the country--and we have 1,800 investigators. They would start an investigation based on that.
It would be very difficult for multiple people to work on the same SIN with all of this information coming in to the various programs for which they're credited, or even for people to work on false SINs and multiple addresses. So it's not just the social insurance number integrity, it's the flagging of these anomalies when they claim benefits; and then the cleaning up of the situation, investigating the situation, is important.