diff --git a/rattail_fabric2/ssh.py b/rattail_fabric2/ssh.py
index 2b27be0..6a88f48 100644
--- a/rattail_fabric2/ssh.py
+++ b/rattail_fabric2/ssh.py
@@ -49,16 +49,16 @@ def cache_host_key(c, host, port=None, user=None, **kwargs):
         # basic command failed, but in some cases that is simply b/c normal
         # commands are not allowed, although the ssh connection itself was
         # established okay.  here we check for that situation.
-        if result.stderr.strip() != "Disallowed command":
+        if "Disallowed command" not in result.stderr:
 
             # okay then we now think that the ssh connection itself was not
             # made, which presumably means we *do* need to cache the host key,
             # so try that now
             cmd = 'ssh -o StrictHostKeyChecking=no {} {} whoami'.format(port, host)
             if user:
-                c.sudo(cmd, user=None if user == 'root' else user)
+                c.sudo(cmd, user=None if user == 'root' else user, warn=True)
             else:
-                c.run(cmd)
+                c.run(cmd, warn=True)
 
 
 def restart(c):