This is only sort of true - if you don't want to get a law school degree, you have to apprentice for four(?) years with a lawyer or judge who "sponsors" you to the bar, and you have to pass multiple tests. So you can't just walk up, take the bar, pass, and practice.
You can write a series of tests instead of getting a university degree. Though you still need to do the 4 year engineer in training before you become a PEng.
Source? I'm aware of programs which allow internationally educated engineers to earn equivalency in Canada (ie. without having to re-do their entire degree), and there is certainly a test to write before you may be a member of a province's professional organisation (and thus eligible for a PEng), but that test is about ethics and engineering law.
I've never heard of any system by which someone without any formal engineering education could write a series of tests to become eligible for a PEng, unless that "series of tests" is accompanied by several years of painstaking study and a bachelor's degree at the end ;)
From my cursory reading it looks like if you went to a school that isn't accredited you can take the examinations instead, but it doesn't look like you can just take the exams and be licensed, they still want you to have some academic qualifications.
I'm a little foggy since I haven't been in school for a few years, but I remember that anyone with a technical degree from a college could write a series of exams rather than enroll and get a 4 year Eng degree.
I'll see if I can dig up a source but I'm pretty sure this is accurate as I actually know someone who has done this and is a practicing P Eng right now.
Many states (and provinces I assume) will allow one to sit for EIT or PE exams given you can provide over X years of experience doing professional levels engineering work under the direction of a licensed professional, where X is generally on the range of 15 years.