Does it matter? The "threads bit" isn't set until you click go. They could totally support zeroing that bit back out. Obviously you and I can imagine how that

Does it matter? The "threads bit" isn't set until you click go. They could totally support zeroing that bit back out. Obviously you and I can imagine how that might be super difficult, but it needn't be. More to the point, not everyone would think that way. They just want an "undo".