It’s quite possible that the MPS is around 65-70%, but not one person can truthfully and authoritatively tell you (aside from (maybe) a CFAI person) what the MPS is/has been, so people ballpark it at 70%. Allegedly, the CFAI website, at one point, said no one has ever failed scoring below a 70%, but I never saw that myself, so maybe someone else can chime in on this.
Ethics supposedly was a tool to determine how to handle borderline candidates (according the the CFAI website at some point).
A rought estimate, albeit not the correct method, is to reverse the passing rate. The last 10 year average pass rate for L2 was 43%, so one must be able to score 57% or higher. My approach is simple. I can score 33% using only a pencil, so if I can score another 33% using some intelligence then I will be covered.
I think you misunderstood the concept. I don’t mean to answer 40 questions correctly and then scribble next 80 by chance and consider passed. I am saying coming to the exam everybody is expected to score at least 33%, so the race is about the second 33%. Much like a benchmark return and an extra alpha return.
I doubt everybody can score at least 33%. If you don’t try and fill in all A’s you may get around 33% given enough questions, but if you didn’t know much and fall for their tricks, your chances of getting less than 33% is very high, as I have experienced with topic tests.