Some days ago I asked a question if will could be treated like would, and received the answer No.Please look the following discussion held between a mother and her would-be daughter- in -law. Why does she say “my son would…”?
Mother: What about your parents? Where are they? Daughter-in-law: They are in America. I see them on thanksgiving. Mother: It is so different–your culture from ours. My son would never think of leaving me and going away.
I agree with what Conchita has written. The “If clause” is often clearly understood and sentences are very often used that way.
Tom’s example was:
This example just happens to be a particularly bad one since he has used a “direct will question” and a “standard” type of short form response. In my opinion, it would be extremely unlikely to hear Tom’s example in a real life situation from a native speaker.
The very least that would have to happen in Tom’s example (to make it a realistic possiblity) would be, for example:
“Well, I would …”
i.e., Get rid of the word “yes” because you are not actually saying “yes”. Technically speaking, “I would (if I could)” is closer in meaning to “no” in the given example.
As I said, I agree with Conchita: There are plenty of times where the “If” clause is understood. The example with “My son would never…” was good, but the “Yes, I would” example is not.