I frequently have to travel trans-Pacific (Far East >> Canada - avoiding the USA and the TSA gorillas) and use Cathay Pacific often.
Of all the carriers only CX has a passenger health warning like this < http://www.cathaypacific.com/cpa/en_INTL/helpingyoutravel/insidethecabin#C > and their concern is sufficiently great to limit crews to two return flights per month.
On occasion, I have to make two return flights in a calendar month and CX flags my travel agent with a Cosmic Radiation warning. Imagine Expedia telling you?
Of all the carriers CX is the only one who considers this, dog airlines such as Air Canada, don't even warn their crews.
I expect to see a Dark Lightning warning on Cathay any day soon!