Is that Fanboy/girl(ism) I detect? Either way, I follow you, and fair enough... But, my point is Rachel's hound marks are genetically permanent much like Bishop's as opposed to the Shi'ar tracking tattoo and I see no good reason why Rachel would decide to add tattoos alongside her "full-facial" hound marks. If anything, I rather she stop hiding them instead of marking herself further as it is not necessary storywise.