Hey Natasha -- I don't think this is possible, but what you can do is to create a link trigger that when someone clicks on a link in your email, they will get that tag. What you need to do is to create an automation when someone joins your form, then add an email sequence that asks the question for the waiting list with a link in it. Those who will click on the link will get a tag and that's how you will determine if they want to join the waiting list. Check out this knowledge base article on how to create a link trigger for your reference: https://help.convertkit.com/en/articles/2502518-how-to-use-link-triggers45

Robert
Free Diver | Adventurer