It seems to me that it might be an awful lot of work for probably limited success. I think unless it was a fresh walker that still looked half way human, they could probably for the most part see the difference, and for them not to notice the real walker mouth would have to be pretty concealed in the mask and thus they wouldn't be able to bite anyone very efficiently. I think you'd end up just causing some brief confusion with limited damage, and then end up with more heads on spikes or something. I think if they are going to go the route of sending walkers into the whisperer's camp they might as well just send a regular group of walkers towards the camp at night. Maybe in waves like at ASZ. And the whisperers are much more vulnerable to this than a walled community is. It depends if they want to start a war right now.

But it would be fun to put a mask on a walker backwards, and then watch it try to stumble away, blind, while it appears to be looking backwards at you, and then gets completely entangled in a swing set. And another walker with a pale on its head and a mask on its butt.

 

I think they're setting up for something like the walker infiltrating at least some of the Whisperers. It may be a short term thing, but enough to stir things up. Not really another good reason to show those eyes opening like that right at the end. However, any interaction with the Whisperers will be totally random as obviously the "Whilker" won't know where to go.

 

Whisker.

 

I can live with "whisker". Especially in consideration of your signature animation.