It is the "cop mentality" at work here. The times I have called/dealt with local police to file a complaint on something, report a crime, whatever, they ask for details that are effectively irrelevant to the issue at hand- i.e. what is my home address, what is my birthday, etc. etc.

Police gather anything/everything with the mental frame of "maybe this person is doing no good, so we better check them out in the course of investigating their complaint/reporting of a potential crime"- i.e. am I "wanted" for something, somewhere so they can get a "two-for-one" if I choose to report something to them. This is both by training and by attitude in my opinion- once you (a cop) do something enough times, it becomes a reflex action no matter how inappropriate it may be.

The likely idea with gathering this information is that they will use it to "analyze" and determine if some people seem to be involved in an ordinate (define "inordinate"- it is purely subjective) number of gun sales. Problem, yet again, is that the law-abiding person (the gun seller) that is trying to ensure the buyer of a gun is properly licensed is the one being scrutinized.

The more dubious aspect to this is that they may be using the information gathered (it seems likely they would also ask 'what gun?' is being sold to the buyer) to continue with a non-approved registry- i.e. a "hidden gun registry" that is not being scrutinized outside the RCMP, and is, of course, also not going to be terribly accurate.