If nothing was unclear or difficult, say so. Skip questions about steps you did not experience; use not applicable where appropriate.

Where did you notice the feedback invitation?
What made responding inconvenient?
What route would help?

Author notes / illustrative keys where applicable:
1. Use this answer to locate the part of the experience that needs explanation. The example issue to investigate is: attendees see feedback signs only while leaving quickly.
2. Inconvenience can locate friction in station placement, available time or the response method. Offer appropriate optional routes and check usability; low participation alone cannot establish disinterest or representative event satisfaction.
3. Turn the requested improvement into a testable next step. One illustrative action is: offer a clearly labeled optional feedback link.