I've been having this problem for a long time and getting fed up.
Calendar events that come from others (e.g. my wife) via email default to my work calendar, a Google apps account. I've set my icloud account as the default calendar but it shows up second in line in my iCal calendars list – and cannot reorder them by dragging.
When I try to switch the assigned calendar from work to icloud, I get "The server responded with an error," yada yada... Both "Go Offline" and "Revert" buttons create duplicate events.