No it isn't. Well I can say without a doubt that if it weren't for my PE license I'd be designing cut rate structures, skimping on rebar, and using cheap concrete. Here's the funny thing IlPadrino, I have to have a license to show something on a drawing, but the guy that's forming the rebar can come in off the street half drunk. Arguably, his job is just as important as mine. And the building inspector doesn't have to have a license. The guy that designs the elevator doesn't have to have a license, nor does the guy that installs the fire sprinkler. So do all these people need licenses now?
My point in all of this is to say that yes, there are bad people out there that will do unscrupulous things, however, it's impossible to pass enough laws to protect all people from all things. I understand that sucks, but what makes us do the right thing, act ethically, and do good work could be a combination of things 1) our customers (if we do **** work they aren't going to be asking us to do any more) 2) making sure people aren't harmed by our work (call it self preservation, fear of a lawsuit, whatever) 3) personal pride in our work. There may be other factors but I have not once in my career made an engineering judgement because I have a PE or because I passed some test, nor do I think those things make me any better of an engineer. Ask those that failed the test what their opinion is.