When I first arrived on the server and got my first keys, I gleefully went to the crates area and began running around trying my keys out on every chest I could find. It never occurred to me to try out the funky sparkling lights.
I finally despaired and begged help from chat and got it.
Since then I have discovered many, many players seem to make the same error I did. It is a consistent question from newbies. They get to the crates area just fine, but then are at a loss as to how to use their keys.
Perhaps making them more recognizable as what you should use the keys on, provide a book (you run the risk of people not reading it!), or something else - but I do think it would be a good idea to make it more obvious what to use the keys on for dimwitted newbies like I once was.