Also, a simple internet search on court rulings concerning taxation will show that the courts have clearly received anti-tax initiatives before and ruled against them. High profile cases from the last five years include actor Wesley Snipes and Flecktones drummer Roy Wooten.
If they really don't want to pay taxes, I say: cut them off from access to any and all services potentially affected. That means no electricity, no water, no use of roads (including walking on them), no schools, etc. See how long they last. Such a "game" would surely be more entertaining than a stormtrooper-like invasion and killing.
