I am with Keith on this, a good technician or engineer will have a feel for this sort of thing, if it's suspect then give the customer a heads up and let them make the decision to proceed

That's the problem with the young mechanics / apprentice technicians now, they have no sort of engineering background, they do not know the difference between mild steel, high tensile or case hardened etc, stick the windy gun on it to save time, will give them a few extra seconds to check their Facebook

Peter