[Miguel]

If people don't want to give it is up to them, the only important thing is the year and the serial number for that year.

Granted that anyone could go and write VIN's down but this way they have an electronic way to do it, if they could cross reference with some other database (DMV's) they could find more information etc..

I'm not paranoid but it's understandable that some people are because identity theft happens.

I'll say to respect their inputs, if they made a mistake and want to change it then it will be ok.