Originally Posted by fate

You shouldn't farm the event unless you really need gold or life crystal. It is better so save gift and use it when you have 2-3 raid points. By doing so you will have a higher priority when people share their boss to public.

This. When you have 2 RP, use one gift or do one upgrade and check RB list. These two actions refresh the "Public RB Share" list for you, which means often (not always but often) you'll see a RB or two (or more) that wasn't there before. If you're THAT concerned, you can run an event map if you do this and do NOT get a RB popping up from it.