Mobs don't see players through 2 block tall plants

What I expected to happen was the skeleton to shoot me through the grass and the creeper to blow up

What actually happened was the creeper just stood in front of me while i was inside the same blocks as the 2 block high grass and the skeleton walked up to me then stood still

Steps to Reproduce:
1. Get a hostile mobs attention
2. Stand inside grass or behind it
3. They ignore you (or if behind it) try to go around to you

P.S. if you are surrounded by 2 tall grass they think your gone and wonder off. =/