In the US we have the title PE, Professional Engineer, which requires some additional qualifications (exams, supervised apprenticeship, etc), and of course a state license. Most people don't bother any more, which has lead to a much smaller number of PE-Engineers many of whom are relegated to being mere license-holders who sign drawings for others, who do the actual engineering.

>So basically, don't call yourself an engineer unless you're willing to sign off on something, and be legally bound by it.

I'm sorry to say it (not really); but for a number of reasons, some good and some bad, the title has been co-opted, and there is no going back.

>This implies a strong background in problem solving and structured design processes

As far as that goes, I've met a number of pedigreed folks who can't engineer their way out of a wet paper bag.