Currently, our invitation features, especially »invitation required«, are designed exclusively for voters. This feature prevents duplicate votes, ensuring only specific invitees can participate. So, an invitation is only used when a user casts a vote.
We are already planning to develop a similar »Restrict voting« feature that will apply to submitters. I'll bring this up at our next planning meeting and keep you updated here. Please note it might take a bit longer than usual, as we're currently in vacation season.