All great questions here!
If I ignore the survey, will the inventor delay/refuse to ship me the item? I don't know. I'm forced to pay attention to the wording of the 3rd party email.
Fortunately, that is not the case. Products will still ship to you despite you not filling out these questionnaires during the campaign. Again, it's really just for marketing purposes during the campaign. However, once a project does conclude (and if it's fully funded), the creator will send out an email to confirm your address and reward level. Here you'll have to confirm it so that items get shipped out to you correctly.
May I suggest that inventors state, up front, that a answering a survey will be either optional or required prior to shipment?
This is a great ask and should definitely be more prevalent in the community. Next time I get to work with Jellop I'll be sure to pass along this note to them!
It's comments like this and dedicated backers like you that keep the integrity of the crowdfunding community strong so keep telling us all how we can do better for you!