Sidechains, which are separate chains that can be interoperable with the main blockchain, might not inherently have their own block rewards. Instead, they might rely on other mechanisms or tokens for incentives. This lack of a block reward in sidechains could make them susceptible to the issues discussed in the paper, particularly the potential for miners to prioritize certain types of blocks (empty blocks or blocks with no TXs): Sidechain cannot be 'reorged' without the mainchain being reorged as well!

The proposed improvements for 'OP_BRIBEVERIFY' involve simplifying the commitment process, ensuring unique usage of OP_BRIBEVERIFY per sidechain ID in a block & using unique identifiers for sidechains to prevent disputes over numbering.