What if the nodes are dishonest?

[Melvin]

This question was answered by @dirvine in another thread:

@dirvine

This one is easier, it should cost you more in work (bandwidth, storage) than you will ever gain. To Farm a coin will be easy early one, but harder later, hopefully the network will be millions of nodes and yours will be part of that, the farming is amortised across the network so like buying more lottery tickets can improve your chance of a win, it’s actually just taking more from you. So you may need to download your 1Mb chunk several million times in the early days and more later on. There will be other costs (encryption) to, but essentially this is the best way to think of it.