You are required by law to give a name and address but you do have a right to know why they want it. If they don't tell you, ask, and then ask again until you get an answer.
Most likely the reason was fairly innocent, but it's not always. Take Benalla cops for example. If you are seen driving in Benalla after 2-3 in the morning they will pull you over to get the same details. Reason given is that if you are driving at that time you would logically be more than likely to be doing something illegal.

If anything is reported as having occured that night, you're the first person they talk to.
I doubt this is what was happening at the spur, however they might be compiling a list of regular users on the theory that hitting the spur regularly is a common activity for hoons. Therefore if you step out of line and you're on the list, you get the book. Just a theory of course to boost ya paranoia.

Little black duck upsets easily. Reassure and give beer.