Still seems like cheating to me. I wish there was a way to catch an attempted block break when you start trying to break it, rather than having to wait all the way for the actual break to go through and then be rejected.
It only works when attempting to open the side of a double chest that is covered. Meaning, if I only have one block covering my double chest I can't open the side that has no block over it.
Guessing the check only applies to the specific chest you're trying to open? Since double chests are still counted as two single chests with shared storage.
I found a new bug, if you try and break a chest with a block over it, it just opens the chest so its impossible to break the chest unless you remove the block above it. This is really odd as left click should never open chests.