I think it would be limited to cabin crew \ pilots - those who actually work on board UK registered aircraft. The correlation that appears to be being used is with maritime law around registration of vessels, flags of convenience and which countries laws are applicable - e.g. where the vessel is registered is key.
It does seem to a dodgy route to be taking ... how easy is it register aircraft in another country, say even within the EU, that has worse local T & Cs and then apply those local T & Cs to all cabin crew and pilots?