Yes, you´re on the right track. Just put a Boolean into the Collection that the form issuer cannot fill out. THen make another page for Approval that selects on all Booleans that are NOT TRUE (false is an entirely different matter, it has to do with the fact if booleans are bi- or tri-logical).
Here you DO allow the approve flag to be set. Try it out and see what unchecked booleans have as a value (prob. null or undefined).