The CC are concerned - but the airlines? they are worried that if they make it sound dangerous people will stop using them (maybe go to New York on passenger liner ?)
A proper safety breifing would say "fasten your seal belt or your head maybe spread over the roof of this aeroplane... "
it would get attention but marketing would go ballistic.......
The real problem is that flying IS VERY SAFE - far more so than driving a car - and teh passengers realise it..........