I've turned off Amber alerts on my phone entirely because they screamed at me with a "terror beep" noise that was loud and jarring enough to possibly cause an accident due to being startled, and it offered no options for customizing anything about them beyond turning them on and off.
On top of that, the government has shown considerable incompetence in dealing with Amber alerts, and burned through much of whatever goodwill the community had for the program in the beginning.
This sounds like a reasonable idea, but I wouldn't expect much from it.