I'm not working in the US, but there are lots of "N" registered aircraft at my country, mostly small companies, mostly business jets and the largest a 737-200.
Does that mean that I can certify for the 737-200 or business jets without attending any type course?
Yes, you can say that the operator should know better, but what if the operator does not, and just claim that "yeah, you hold an A&P, you can certify our aircraft".
Most of these operators are not US registered company, but local companies, but they operate "N" registered aircraft as well as local registered aircraft, for reason unknown to the universe...