Ughhh, that's insane.
Not really. This is for deploy systems which deploy to a trusted environment (for instance through VPN, network security etc.).
This allows you to verify hosts while having never seen their keys. Just totally shutting off verification is a horrible idea.
I don't disagree with this, but if you can MITM my traffic then impersonating SSH is the least of my worries. The chance that I will randomly SSH into a machine is pretty small to begin with whereas the deployment tools themselves for instance will push out code changes in regular intervals throughout the cluster. My point is: if you can actively MITM my traffic or anything similar in severity, then there are much more interesting targets than SSH.