One of life's little oddities... illegal to drive with headphones, but not illegal to drive if deaf.
I would imagine this is because wearing headphones is preventable, while deafness (not caused by hearing damage) is not.
It would be that much more of an imposition if deaf people couldn't get anywhere without having to take public transportation or having a ride lined up.
Most of the time I'm using my headphone jack it's to plug into my car stereo and the level at the warning is not very loud.
I've found that after marshmallow just keep pressing volume up and it goes away
I could have sworn that I've already tried that before, and as soon as I bought my Galaxy Note 4 and turned it on, the upgrade to Android 6 Marshmallow was available, so I've had that the entire time I've been using it.
ATTENTION ALL POSTERS ON THIS THREAD
Don't be upset with me if this doesn't work, please, because I only found this a moment ago, did it, and tried adjusting volume both with my Bluetooth headphones and through the phone's speakers, but so far it seems to be working.
Check out:
http://www.samsungsfour.com/tutoria...usic-volume-warning-on-galaxy-smartphone.html
The article suggests that you, and I quote: "
1. Open the 'Music Player' and go to 'Settings'.
2. Now give a check mark to 'Smart volume' and you will get a warning like the one shown in the sceenshot below, now click 'ÖK'."
The Smart Volume control will initially say, "The volume of all tracks will be adjusted to level 2" (at least it did on mine), but I adjusted my volume all the way to 15 (with no warning pop-up, but I'd forgotten to connect to my Bluetooth headphones before doing so), disabled Smart Volume, enabled it again, and it said "The volume of all tracks will be adjusted to level 15".
I then connected my Bluetooth headphones, adjusted the volume down, and back up again, with no pop-up. It works when not on Bluetooth as well, but if I'm not mistaken, the pop-up was never an issue when using the phone's speakers.
So, like I said, it seems to be working for me, without rooting, without downloading any app, just a simple adjustment in the Music app's settings. I always assumed I would not want Smart Volume enabled, because dynamics are there in music for a reason and I assumed that, if anything, it would LIMIT volume when I didn't want it to...but if it gives you the option of adjusting everything to max, PLUS disables that annoying pop-up, I can't see why I shouldn't leave it enabled.
I cannot speak to how it will affect using more than one music app, or video player, or what-have-you, but the only time it's been an issue for me is using the Music app, so this solves my dilemma. Man, I hope I'm not so late posting this that it won't be of any use to anybody.
By the way, that article was the second result on Google Search, right below this one, so some of you may have come across it. But if so, why didn't YOU post it here?

Joke, joke...and since it's nearly Christmas, happy holidays to you all!