Some questions:
What do you think about multiple locations and or logical locations as stated in the specification?
Indicates one or more physical or logical locations associated with the object.
At first I thought one could get around by using a property like Mobilizons isOnline. But as it seems a valid use case that in the future one only wants to reveal an online-link or a physical location to accepted attendees this is not possible anymore.
At OFFDEM we discussed about also noting whether the event has a physical location (secret or just not known yet) which would also cover hybrid (on and offline) events.
Looking forward to hear your thoughts!