FCP File Management Question

Hello!

I have finished the long process of importing all my mostly unedited video (about 9 years' worth) into FCP Libraries. Sources include iMovie, an iPhoto Library in which I had saved all the movies from still cameras and iPhones, and finally a bunch of MiniDV tapes (which were a real pain due to an unfixed bug in FCP). All the media are now in 3 pretty massive libraries totaling over 4 TB. My plan is to create "year libraries" for each year and edit from there. I have noticed that when I copy media from one library to another on the same hard disk (actually a Drobo) that it happens instantly / there is no progress bar in the "background tasks" window. I assume from this that FCP creates pointers to the same media from different libraries as there is no duplication. I further assume that as long as media is referenced from at least one library that the system will not "delete" it / release the space and allow it to be over-written.

I wanted to be sure this is how it works since my planned workflow will involve "draining" the 3 libraries into the year libraries as I create them - once media is transferred / referenced in, say, the 2009 library I will trash the original Events in the iMovie, iPhoto, and Tape Transfer FCP libraries. I want to be sure not to lose any data in the process. Any help or other suggestions are appreciated!

Bob