potential double-spending?

[Zhiqi]

Thanks for making this wonderful demo.

I have a question about how to prevent double-spending.

In coinbase block #5, if I change the first transaction to "$2000.00 from Jackson to Alexander", it will pass at nonce=10042. Since Jackson does not have 2000, do we have a double-spending issue here?

[Anders Brownworth]

No, because the other peers don't agree on the final block's hash.