I think it's prudent of mappers to lock their work, doesn't take a rocket scientist to go in, mess things up, and then say, "Well, so and so mapped it, and now it's fucked, must be their fault!".
My ECU was locked by Will, just recently I asked for it to be unlocked (over 12 months after he did the work), and he was accommodating. Given the problems I've had just recently with head gaskets, I never actually got around to getting it unlocked, but the option was there.
Will appears to have done a great job with my car, and that was backed up when the head was removed, a more clued up friend of mine, commented that it looked perfect. This is not to say I wouldn't explore other options down the road, but I wouldn't tell anyone to avoid him.
He mapped my car 18 months ago.