For the curious, I can tell you this is certainly not a global effect. At the UK university I work at, we mark work out of 20, and only a small proportion of students get above 17 (considered excellent, probably equivalent to A).
I attended the International School of Brussels for my high school education, and most teachers were from the UK. I can vouch for the difference in culture regarding grades. I once had an English teacher tell me I should be "leading the class" since she had given me an A- the semester before. Such an attitude was prevalent among all my teachers, and I felt it really damaged my college application to American schools. I applied to stanford and of the 4500 early applicants, 2500 had a 4.0 GPA (perfect). Not one student at my school had an unweighted 4.0. I had a measly 3.4.
Other than the comparative nature of GPAs in college applications, I thought it was a great approach. The only class I was able to coast through was Math, but I was one of the few who could do so.
