Ssh – Disabling openssh host key checking on LAN

If I want to specify for LAN addresses that I don't want to deal with host keys, how do I do that?

/etc/ssh/ssh_config
Host 192.168.*.*
   StrictHostKeyChecking no
   UserKnownHostsFile /dev/null

or

UserKnownHostsFile none

even with

CheckHostIP no

Isn't doing the trick. openssh 7.1p1. With no known_hosts file in ~/.ssh or /etc, I still get:

The authenticity of host '<hostname> (192.168.2.2)' can't be established.
ECDSA key fingerprint is SHA256:.....
Are you sure you want to continue connecting (yes/no)?

This functionality was somewhat recently changed in openssh. Old questions suggest the ssh_config as shown above, which doesn't appear to work anymore.

Yes, this is a horrible idea. I want to do it anyway. It risks a man in the middle attack. It risks connecting to the wrong server if there's a configuration issue. I'm just tired of having to remove entries from known_hosts with the multiple VM's I have that often change fingerprints, and am willing to live with the risks. Yes, there's other questions like this, that explain how to do it the right way, but I don't want to do it that way. I just want to turn it off.