I strongly dislike hearing refs warn people to not commit fouls when they aren't committing them.
That scary skeleton looking lady ref with the giant mouth does it all the time. I hear a few other refs do it too, but she's the worst.
If a guy posts his hand on the cage, she's right there, warning him not to grab the cage when he's not grabbing it.
Shut up and let the fight happen. If a foul is committed deal with it because you're the ref and that's your job.
To me the ref is changing the dynamic of the fight. The fighter has to focus on something that isn't even happening and not on what they're doing. 
Agreed.
Warning them not to grab the fence when they simply rest their hand against it is a problem. Has to stop.
They also need to stop doing nothing when fence grabbing actually happens.