At the moment the type of the scan have to be decided when creating a survey. It happens sometimes that I do one thorough survey with active scanning and later some quick passive ones to verify design. I’d like to use snapshots feature for that, but I can’t at the moment.
It also sometimes happens that I start with active scanning, but will decide do drop that idea later for some reason (time etc). All data for passive survey is actually there, but to complete passive survey I have to drop all data or finish survey in active mode to waste time for waiting for data I’ll not use anyway.