When blacklisting a harvest level, say shovel;1;-1, I expect that only shovels of harvest level equal to or greater than 1 will prevent the match.

However, the blacklist logic tests each separately and first tests if the item is a shovel. If it is, the rule match immediately fails and the harvest level range isn't checked.

I would expect the match to fail if the held item is a shovel AND within the range specified.