There are two types of events at ROCO: internal and external events. So what's the difference?
Internal events are sponsored (supported) by a ROCO chapter, with full chapter involvement (volunteers and possibly funding), whereas external events assume little involvement from ROCO members and chapters, as described below.
Internal events go through a "proposal" and "approval" process, whereas external events are based on a simple venue rental contract (which is much faster and easier). If you make an event proposal (suggestion) that does not pass the chapter approval, you can still organize it as an external event.