You have a form set up in Sphere. For example, you offer 2 free tickets through the form, but don't want users to fill out the form more than once to gain 2 additional free tickets. Is there a way to prevent users from filling out the form a second time?
There is no setting which can be applied to prevent a user from registering again. The best way to deter additional form submissions is to add text to the form indicating the user should not fill out the form more than once.