Also reference https://support.microsoft.com/en-us/help/310316/how-permissions-are-handled-when-you-copy-and-move-files-and-folders for the Microsoft explanation of how move vs copy works. We get the same behavior regardless of whether move/copy is performed by BESClient, Windows Explorer, command shell, etc.
There are policies that can be applied to Explorer to modify the behavior. I haven’t tested, but I don’t expect those policies would have an effect on copy/move commands performed by the BES Client or command shell.