It is a funny situation. They tell you to turn off ALL electronic equipment. ALL should include hearing aids, pacemakers, neural stimulators, diabetic insulin pumps, sphincter controllers etc.
So turn off the hearing aid and cabin crew instructions cannot be heard - but the PAX has followed instructions!
And of course nobody follows those instructions to the letter - even if, with some implants, it was possible.
So, NO, you cannot always strictly follow CC instructions. Now OK, you could say that because of that, the PAX with the fittings will be deplaned. I suspect the resultant court case and the newspapers (especially in the US with the ADA act) would lead to the usual interview without tea and biccies.....