Do you modify the block or do you not modify the block?
If you don't modify the block, it still pays the mining reward to the same account. So you've just done what everyone wants you to do.
If you do modify the block, it won't be valid anymore until and unless you mine it. That leaves you two choices:
1) You can ignore this block and mine some other block. But then someone else who mines on top of this block will have a longer chain than you and you won't get any reward. So why would you do this?
2) You can mine on top of this block. Well, that will just help ensure the person who mined that block gets their reward by producing an even longer chain that includes their block.
A block contains: Version, HashPrevBlock, HashMerkelRoot, Time, Bit, Nonce, which one of these is the miner identifier. – Utsav Mitrakaushi Basak – 2016-11-14T11:25:02.723
@UtsavMitrakaushiBasak None of those are. The coinbase transaction specifies what account the mining reward is paid to. The HashMerkleRoot is the hash of the Merkle tree of transactions, including the coinbase transaction. The whole point of mining is to secure the transactions. – David Schwartz – 2016-11-14T11:28:16.697
Understood, as in the transaction for the reward is included in the block, so no matter who confirms it the reward will go to the sender right? – Utsav Mitrakaushi Basak – 2016-11-14T11:31:04.763
4@UtsavMitrakaushiBasak Everyone confirms the same block. The whole point of mining is to bind the transactions into the block so that they cannot be disassociated. There is nothing but the block. There isn't a block plus something else that claims it somehow. The block is the claim. – David Schwartz – 2016-11-14T11:31:53.083