Penalising people for leaving the question blank pretty clearly defeats the point of using negative marking to cancel out guessing.
With regards to differing pass marks, it seem pretty clear that someone who gets a 60% at one university could get a 50% or a 70% at another and the grades are awarded accordingly. At my university 40% is a pass, 50% a C, 60% a B, 70% an A. According to the uni's webpage on grading and how it works with foreign exchange students, a grade A or A+ student from the US would be a grade A student here, a grade A- or B+ student from the US would be a grade B here etc. So the systems are pretty similar in terms of actual ability required to pass, they just differ in terms of how the exams are set up. Otherwise my university with its 40% pass mark would be nowhere near as high in the rankings as it is.
With regards to differing pass marks, it seem pretty clear that someone who gets a 60% at one university could get a 50% or a 70% at another and the grades are awarded accordingly. At my university 40% is a pass, 50% a C, 60% a B, 70% an A. According to the uni's webpage on grading and how it works with foreign exchange students, a grade A or A+ student from the US would be a grade A student here, a grade A- or B+ student from the US would be a grade B here etc. So the systems are pretty similar in terms of actual ability required to pass, they just differ in terms of how the exams are set up. Otherwise my university with its 40% pass mark would be nowhere near as high in the rankings as it is.