he did bring up that crippled and immobile Zs were an issue.
You can see them, no problem. easy to take out and you know you got them.
You start going through the grass or mud and one is laying there in wait and you step on it, then it's a problem.
you start going through ruins, wreckage and plain ol' overgrown foliage, you gotta watch your every move and if you step on one, that's a problem.
In Muhammad's segment, he brought up how the draggers were always an issue because if they catch you offguard, they could get a chunk out of your leg before you even noticed them.
Granted, It's zombie fiction, you always overplay how dangerous the zombies are.