I suspect that the Mark, like many things, is rather more powerful in MoR than in canon.
Where ‘many things’ includes ‘simple consistency’. Although come to think of it the characters are more consistent in canon while (magical-)physics is more consistent in MoR. A difference in emphasis.
...unless you use a Mark. Which only a dictator can require.
There were still traitors. Snape was Marked, and spied. Karkaroff was Marked, and ran.
I suspect that the Mark, like many things, is rather more powerful in MoR than in canon.
Where ‘many things’ includes ‘simple consistency’. Although come to think of it the characters are more consistent in canon while (magical-)physics is more consistent in MoR. A difference in emphasis.
Yep, thanks Pavitra.