One of the differences between American and German schools is whether a student's grades are regarded as private or not.
Here at the MLS, I've seen teachers reporting grades to their students by reading them out loud in front of the whole class; whereas in America, grades are generally seen as something private, between the teacher and student (and perhaps parents).
The rationale for grades to be public (as it was briefly explained to me by one teacher) is that it allows the students to compare how they're doing against their peers and to check that the teacher is giving them a fair grade in relation to the rest of the class. My students do not seem to be shy about their grades and willingly share them with the whole class.
In America, I remember grade sheets being posted with students given ID numbers so that no one else would know who had which grade. Also, my fellow students would try and hide their returned tests so that no one else could see how they did.
Because their grades have always been public, these students are accustomed to them not being especially private. And also, if someone isn't doing well and will be repeating a year*, everyone will find out about that anyway. Partly, I think this is a result of the students knowing each other better at the MLS. There are fewer students per grade than I had in high school, and students often stick together in the same classes for years on end.
So the big question is: Which leads to a better school environment? I think the teachers should feel the freedom to give grades individually and personalize the learning experience for each unique student, but at the same time, it helps students know where they stand when they see how their classmates are doing. And even if the grades are given in secret, classes usually know in general how their peers are performing. So, I think I'll still hand out grades in private, will continue to ensure that the class knows how they are doing as a group (providing grade tables (Notenspiegel), and the like, which is also quite common at the MLS). And the class should have some sense of how the whole class is doing.
*Repeating a year at the MLS is much more common than I've seen in the U.S.