If BL unlocked officially, warrenty is VOID, no more official updates and DRM is lost.
U lose DRM for ever if BL is unlocked by official method. TrackID app willnot work.. this is what i have in my knowledge.
I never minded in unlocking it.. since i dont use it.
If you know what you are doing, then no problem at all.. so i unlocked BL officially.(no option,, manufactured 12w14)
If unlocked by unofficial method, then u can relock it.. search in the forum to gain more knowledge..