[StevenRayOrr]

Your first sentence isn't supported by your second and third. It is incredibly common to track not just interest but level of interest -- and lots of companies find it a valuable metric for marshalling their resources. Is this perhaps not the best way to get that metric? Now that can be a helpful question to ask and a good thing for this dev to think about, rather than outright dismissing the attempt.

[Exuma]

I'm more just saying that I don't think people doing/not doing that action is a good indication of their interest level. My interest level could be an 8 out of 10, but there's no way I'm pestering my friends about it.