At the moment, an event is either public (with all details visible) or admin only. If it's public, info like date, time & location can be seen by anyone. There is the ability to limit ticket purchasing to members only but this doesn't stop random people showing up at your event because they have location info. If it's admin only, members can't purchase tickets without manual processing by an admin.
It would be useful to have a setting for events where you could make the entire event just visible to a Group (like Members) so this information is unavailable to the general public but members are still able to buy tickets.