a) If you aren't touching that land mine you're missing the point. You can't say that one is free (except maybe it has a cost), and the other has a cost. That's just nonsensical.

b) Second, I'm going to argue that tests are actually free. And I think this because I don't care how good static type proponents think they are, I know they don't wait until it compiles and SHIP SHIP SHIP, they actually run their damned program. The alternative to automated testing is manual testing, not no testing.