Especially if a number looks wrong. This site records its own history, and a park it has misread is the single most useful thing you can report — I can’t see it from here.
Your message is stored so I can read it, and emailed to me. If you leave an email address it’s only so I can reply, and it isn’t shown anywhere public. The site records a visit row that includes your IP address for 60 days — the terms page says exactly what that is and why.