To kick this off, even though arenas are in the "Beta stage" because of the memory leak, I want to say that in my arena, "attackatsea", you can't open a single chest there. I care a bit much about this issue since there's a whole gimmick involved with all of the chests in there. The spawns are also a bit off, I would like to be contacted about those sooner or later.
(For those who don't know the gimmick in attackatsea, in each of the chests you will find Flint. (Hee hee.) You should collect all of the Flint in the chests, (Difficult, I know.) and once you have or think you have enough, there is a drop chute on one of the boats. If you drop enough Flint there, (You have to get ALL of it for it to work, or sacrifice some items, because you can't take back what you put in there.) a chest uncovers. This chest is filled with goodies necessary for your crew's survival.)