Where I practice in Ontario, Canada, the Engineering Act legislates that engineers are only allowed to practice in areas in which they are competent. We have a responsibility to the public to keep them safe over all else. My assumption is that most other jurisdictions in the world have similar legislation.The take-home message here is simple: if you don’t know what you’re doing, don’t do it. You can’t possibly do a good job, and you could be putting people in harm’s way.