I often use the great 'Participation Options' in the Web View. With it, I can, for example, create the Yes/No option 'VIP' for an Event, and I can mark the VIPs in my list of participants.

Usually there are not that many VIPs in relation to the total. However, if I want to filter the 'non-VIPs' I cannot. That's because when filtering, you can only tick the Yes's or No's. I would have to set all the other participants to 'No' first. A lot of work. It would be easier if you could select the option 'empty' when filtering on boolean fields.

Also, you cannot change 'Participant options' in bulk, as you can with the RSVP and Attended.