I\'m coming from the Java world and reading Bruce Eckels\' Python 3 Patterns, Recipes and Idioms.
While reading about classes, it goes on to say that in Py
About sources (to change the access rights and thus bypass language encapsulation like java or C ++): You don't always have the sources and EVEN if you do, the sources are managed by a system that only allows certain programmers to access a source (in a professional context). Often, every programmer is responsible for certain classes and therefore knows what he can and cannot do. The source manager also locks the sources being modified and of course, manages the access rights of programmers.
So i trust more in software than in human, by experience. So convention is good but MULTIPLE protections are better, like access management (real private variable) + sources management.