You know, I seriously thought about this after posting.....
Does you 3 year old go to "school" 7 days a week?
Plan this for over the weekend, when you're the only one that has to deal with it, if you're so concerned what the teacher would think.
2nd...and this is NOT a joke, because I use these myself....get a pair of these....
Don't worry, you'll still be able to hear her when you're wearing them. If she gets into real trouble, you'll know it.
Also, it's obvious you can shift one of the earpieces a half an inch so it looks like it's covering your ear, but you can hear everything....so you're not neglecting or abusing her.
However, before you put them on, tell her "I can hear you when I'm wearing these, so you can cry all you want."
That'll probably piss her off for a while, and she might scream even more.
Good....she'll tire out that much faster, and you won't get a migraine.
More importantly, she'll get the message loud and clear she's not being listened to. She doesn't have to know you can still hear her.
However, you can wear them full on and will simply hear a muffled crying/whining. You'll know it if she's trying to tell you something important...hopefully "I wanna eat"
I wear these when I'm trying to read and the TV on. I can still hear the TV but it cuts it down so it's not distracting. When someone calls my name, I can hear them, and move one side to hear and talk.
If you have a husband....get a pair for him too.