Is there a possibility of scooping the PoW in an invalid block? The process would be something like this: You'd connect to as many nodes as possible and watch all incoming mined blocks. When your software sees an invalid block, your software would submit a valid block with the invalid block's PoW. Your valid block would contain no transactions, in order to guarantee that it is valid.

I suspect this is not feasible, but I don't know why.