Growing legumes from cuttings

I would only think it worth chopping seedlings up if they were valuable as, for me, it would be just extra time and effort for very little gain. If you saved your own broad bean seeds, the odd casualty would be better put in Mr. Greedy the composter.
Having said that, I just potted up a seed potato sprout that i knocked off a couple of days ago to see if it would root but to me they are more valuable. If it grows, I'll see what the yield is per sprout.
I remember reading about cucumbers being able to be re-rooted it the roots rot on the seedling - just after I had binned an F1 female one with only 4 seeds to the packet.