It's very annoying! I hate it! Fortunately, you only get it once after you reboot/turn on the phone - which is a minor consolation I know! I swear it is going to cause me to get into an accident one of these days when I have my phone connected to the Bluetooth in my truck and I get that message!
On my old galaxy s4, you could go through the adapt sounds setup and click that you couldn't hear anything. After telling the phone you're basically deaf, the notice would stop. I didn't do it personally, but I heard it worked.
My previous LG had it too. I feel like they're required. Or trying to avoid potential lawsuits. Not sure why they can't just throw it into the terms and conditions.