Bukkit

 ♦ Version 1.4
    Info:
        Changed reload command! No more typing the original "reloadblockcommand", or even "blockreload". Now it's just "block reload". One command, one subcommand. Easy, consistent, reliable, and simple.

Sound, if set to true, will play when the player types /block, whether or not they have any items to compress. The message performs similarly. If set to false, neither have any problems.