[somebody_amzn]

They can be fiddled with at will, the boot loader stack has been cracked for those a long time ago.

Microsoft didn't bother to fix it. (look at the WPInternals project, through which this is possible)

For the Surface RT, they didn't push firmware updates to fix the bugs allowing to unlock it either.

[ZoomZoomZoom]

Sorry, but I'm not speaking about reverse engineering. WPInternals doesn't work reliably on all models and it's understandable. As others said already in sibling comments, RE shouldn't be necessary at all.