If there isn’t, this is as good a place as any to make one up.
The ostrich defense.
The Freeyrol* defense
Three year old.
Does anybody actually do this in real life? I’ve never seen it.
Willfully blind/deaf? Immature?
Really?
A peewee-herman.
My boss will do this!
When I tell him how much he and his 9 year old son are alike I don’t always mean it as a compliment…
Shit For Brains.
I call it laylering (after the “laylerlaylerlayler” sound some people make while doing it).
“I caaaan’t heeeear youuuuu” in an annoying sing-song voice.
Similar to “neener neener neener” which is when someone has or gets to do something that you didn’t.
Both represent emotional maturity levels of about a first-grader.
Really. I’ve only seen it on sitcoms or cartoons. Maybe kids are picking it up for laughs, but I’ve never seen that either.
I’ve never seen anyone do it in real life either other than in jest. Not even children.
I’ve seen adults do this. It’s really sad.
My brother and I would do something similar. We didn’t have a name for it, but it was the moment during an argument where we both knew it was going to end in violence.
I think I missed where this joke was set up properly. It’s supposed to be
Q. What do you call someone who puts their hands over their ears and goes “Na na na”?
A. Anything you like, they can’t hear you.
But it seems like it isn’t? 
I kind of assumed it came from a cartoon or movie or something. Someone had to come up with the idea though.
Rats, missed the edit window.
Maybe it’s a twist on the “hear no evil” monkey?