What not to do in a survey

I purchased Mario Kart Wii and decided to register it at Club Nintendo. It’s an interesting service and I’m playing along to see where they go with it. If you want to register your own Nintendo games, you can find it on the back of a bifold pamphlet included in the game case. Some older games refer to the service as “My Nintendo” — if you had an account there, the system will automatically send you through a transfer process when you log in. Anyway, after entering the registration code, the system prompted to fill out a quick survey about my purchase. The final question read as follows:

Please share with us your thoughts/comments about Mario Kart Wii. (255 character max)
I didn’t have anything, so I skipped it. Nintendo didn’t like that, and kicked me back to the survey. There was no error message at the top, I had to scroll through the survey to find this message above the comments question:
Please enter your comment
I replied thoughtfully:
Don’t require comments. And if you are going to require them, don’t say “please.”
What have we learned here: * Don’t require users to fill in a comment block on a survey * Place some form of error message at the top of a submitted page * Frank plays Mario Kart Wii (it’s really good)