I find it's enough to suffix (or prefix) a method or property with an underscore. If calling code uses it knowingly, then they should know it's bound to break

I find it's enough to suffix (or prefix) a method or property with an underscore. If calling code uses it knowingly, then they should know it's bound to break in future. The overhead (cognitive, and possibly execution) of not exposing the property isn't worth it, I think.