The issue with professional licensing, is that it's very, very specific.
In things like civil engineering, there's usually mandated context. You have to work within certain parameters, so it's not too difficult to test with real-world criteria.
With software engineering, it's all over the place. In fact, one of the most exciting things that I used to look for, in potential candidates, was people who were not bogged down with dogma, and would bring alternative viewpoints to the team.
Since anyone coming into my team would require a ton of training; regardless of their seniority, I always had a nice, long on-ramp, in which I could evaluate people.