I threw together a quick test and it looks like that works. It logs out this when it doesn't have anything to lock:
09:03:55 Trying to acquire lock on [nothing]
09:03:55 Lock acquired on [nothing]
Which is better than what it said previously, something like "no resource specified - probably a bug." There were a few times people were misled by that message. I think that's good enough to close this out.