Building the form is the easy part. The hard part is getting the link in front of people at the moment they are willing to answer. Nobody types a long docs.google.com address off a whiteboard, a receipt or a banner, and thirty students typing it wrong means thirty lost responses. A QR code removes the typing: print it in the corner of a worksheet, stand it by the register, staple it to the permission slip, or put it on a conference badge or a waiting-room poster, and the form is one scan away. That timing is the real advantage over emailing a link later. At an event you are competing with the walk to the parking lot, and afterward you are competing with an inbox.
Two details decide whether the printed code actually works. First, the form has to be published. Google's current model separates writing a form from opening it to responders, so a code made from an unpublished form scans into a dead end. Second, a Google Form has two completely different URLs and only one of them is safe to print. The responder link contains /d/e/ and ends in /viewform, or it is the short forms.gle version, and it opens the fillable form. The edit link ends in /edit and is what sits in your own address bar while you write the questions, which is exactly why people copy it by reflex. Anyone scanning an edit link hits a request-access wall and cannot answer. If the link you are about to paste ends in /edit, stop.
After that, very little can go wrong. The responder link is tied to the form's ID, so editing a question, renaming the form, changing the theme or adjusting settings never creates a new URL, and one printed code can front a form you keep rewriting all year. Two things do break a code already in the wild: unpublishing the form, which closes the link to responders, and deleting it. Switching to a duplicate made with 'Make a copy' leaves the code behind too, because the copy is a new form with its own ID and link, so keep editing the original. Saved QR Cake codes are dynamic, even on the free plan, which gives you a fallback the raw Google link cannot: save the code to your account, open it in your dashboard, paste a different responder link, and every printed copy follows. That is how last year's field trip consent form becomes this year's, and how a pre-event sign-up form becomes the post-event survey with nothing reprinted.
