Bookmarklet: Switch account from Google Forms
Click and drag to bookmarks bar: Forms Switch User
window.location='https://drive.google.com/accounts?continueUrl='+encodeURIComponent(window.location.href.replace('formrestricted','viewform'));void(0);
Google Forms are sometimes restricted to users from a certain Google organisation, and accessing this when logged in to a different Google account will produce an error message. Unfortunately, this page does not contain a link to switch users. This bookmarklet redirects you to the Google Drive/Forms account switcher, and allows you to switch accounts and return to the form.