Honestly its up to the field and the hosts not the opinions of one individual!!!
If players are playing at an event or field that allows their use or the use of DD's then the player(s) that don't want to hear the noise should bring their own appropriate hearing protection! Plain and simple and if they are totally against them then don't attend most milsim games. Another great option would be too find a field or place to skirmish where you can play or a paintball field and don't worry about your ears and the realism involved with airsoft.
This is after all a sport trying to replicate and depict modern conflicts and realism as much as possible!! Also the potential for injury sustained from airsoft is far greater coming from a bb then a a quick noise and some slightly cold co2/air being released lets be realistic here!!! Also for the record many and I do mean many indoor airsoft arenas across the world and also outdoor arenas that contain buildings allow the use of DD's. When not thrown directly at/ beside some one they are perfectly safe and do their job just enough!
But believe me they are no where close to the real thing! Not even half as close to a Tflash(training DD) So if you want to compare injury potentials a simple Google search will show you the the results of various airsoft related injury all the while playing with protective eye ware!!!! Yet are all players forced to wear full face masks a mouth guard and tacti-COOL earmuffs for ones ears in case of a bb? Wait shouldn't they wear a cup too????
NO!!!!!! They are not forced or made to wear extra gear when playing this game! That would be truly ridiculous!! Most adults know what they've signed up for when they sign the waiver and if they're not ok with that don't sign and find another venue or place to play!!!!!
Also yeah it does have a warning label as even a plastic child's toy must and random signs for that matter!!
References(for comical intent)
-http://underscoopfire.com/wp-content/uploads/2013/07/SAFE-TOY-label.jpg
-http://www.colinfahey.com/funny_images/warning_label_sign_has_sharp_edges.jpg
I'm sorry but its not even close to the Db level of a .22 cal!
http://ballseyesboomers.blogspot.ca/...d-tactics.html
So to all of those who don't want the realism of DD's and Smoke omg that to in very very large amounts can be dangerous if inhaled while running through the smoke your using for cover... ohhhhhh nooooo... wait this is a milsim game right??? ... I DID sign up for and am trying to replicate and play?
The point is they are commonly used toys to replicate somewhat similar of a response to a real DD. Yet in no way come close to those Db levels and yield a similar reaction! Perfect for civilians and people trying to replicate something similar but not create the real thing!!!!!
Cheers,
Ghost