Probably quite difficult in practice, unless he/she could somehow convince a mining pool or something. Another option would be to set up mining hardware in a p

Probably quite difficult in practice, unless he/she could somehow convince a mining pool or something. Another option would be to set up mining hardware in a place like China with low cost electricity. However, this would take time, money and serious effort - if you cash out ether to fund it, you likely crash the price, and if you succeed in fighting the hard fork, the split in the community would likely destroy the trust in Ethereum and your funds go poof.