The caveat is very true, and I think that I would be unhappy if a licensing body told me I'm suddenly "not qualified" to do the work I've been doing well for many years. Besides, it wouldn't be just for me to bear licensure costs (whether direct or indirect by being out of work while I get licensed) to correct an ethical fault in companies.
Perhaps licensure could be an effective solution, but one that is not very empathetic to engineers. Maybe some kind of a government-owned ethics controller/body to handle unethical software would be more just for engineers. Although it could also be very inefficient.
