How can I collect signups without collecting email addresses?
Use a privacy mode that turns off email collection entirely, so people can sign up anonymously. For cases where you keep the list but want to hide it from other respondents, use an incognito mode instead.
Likely causes and how to fix them
You don't need identifying details at all
Turn on strict privacy mode to disable email collection, so responses can't be traced to an individual.
You need the list but want responses kept private from each other
Use incognito mode, which hides other people's names and emails from respondents while you still see the full list.
Anonymous responses with strict privacy mode, or hidden responses with incognito mode. Turn off email collection