I mentioned this in an earlier reply. This no headphone rule doesn't seem to apply here in the US. With the exception of noise cancelling headphones that are supposed to be switched off under the 10,000ft ceiling I am permitted to keep my headphones on when travelling with UA. Because other electronic devices are banned under this altitude my only option is to plug into the on-board audio and I continue to receive any PA announcements so maybe I've answered my own question but this goes back to the point that the rules are different depending on which aviation authority you are subject to.

The other rule that differs between here and the UK is the mobile phone one. While flying on a domestic carrier the moment the wheels touch the tarmac you are allowed to fire up your mobile but when on a UK one (even when landing in the US) it is verboten until the 'plane is safely at the gate and the seat belt signs are off.

So perhaps our beef is the inconsistency between the different rules set by different aviation authorities.