I would not buy a miner that hadn't proven itself mining on the real net. Testnet is not the same.
lol what's the difference? If you wrote something like this I bet you would not be able to tell by the cgminer screen on which net you are currently on. Hint: the only difference is the difficulty value. Totally unimportant for the hashrate or any other miner functionality.
Bitcoinrama already admitted they were paying some hacker (who helped them last minute debugging) with that mined coins, which is shady as hell. Would it be legal to do if that machine was not a BTC miner but, for instance, printing press instead? Of course it would be illegal.
Not "some hacker", but their employee.
Your printing press analogy is wrong - if someone working at a government mint solved a particularly difficult problem, they'd probably get a bonus on top of their salary. This 1 BTC is the same.