The liquids on airplanes thing is, surely, because if you want to fly into the US you have to comply with US security requirements, so any international airport has to implement the same rules. That this results in increased sales in airports can only be coincidental. Note that the laptop ban didn't happen because the rest of the world (and their own business travellers) talked down the Americans to just a more detailed inspection regime.

I have difficulty taking Murray as a trusted source at this stage.