So she got banned for shooting throught a corner of a block..? Thats totaly legit, i done that myself in my servers (Not BL) and mojang should know about this "glitch" and if they didn't fix it, then that shouldnt count as a glitch, but a Opertunity for bow pros to shoot throught corners.
BrokenLens Forums
TediTheWarrior
Thats just my opinion 
TediTheWarrior
If a arrow goes throught a legit Wall then its bannable but theres technicly a tiny hole between the blocks since its a corner thats why a arrow can go throught it. If he put 2 blocks in the corner then its not possible to shoot him.
https://www.brlns.net/forums/threads/can-i-be-unbanned.31095/