I don't think they were handing out 6 pack licenses exactly like penny candy. I sat for the test back in '83, I remember studying like hell for it. It wasn't easy. I passed it no problem, but there were a lot of people who routinely failed that test back then.
Could be there were some who lied about their sea time, but that probably continues today.
My understanding is that now that the test is in the hands of schools rather than the USCG, the pass rate is higher, as the schools are invested in having the students pass.
I was talking about late 60's through most of the 70's. (I guess that is more than 30 yrs ago. SHEESH) I could be wrong, but if CG passenger boat inspections are any indication, I think which CG Dist. you were in may play into it as well.