More to the point: not spending is not voting, but not spending but actually using the good sends a totally different message to both the industry and the government.

Can one have an effective hunger-strike while eating?

Actually going on strike and not consuming would/could send a 'high-road' and morally correct message. Self-deprivation innately states the value of the belief. Refusing to pay while continuing to consume only reinforces that the item of consumption is where the value actually lies. It makes people look doubly foolish for claiming that they won't pay because the item has no value.