It gets more interesting with branded goods which are completely fungible. In theory they have a global MSRP or at least a globally optimised one, to avoid arbitrage, and brands get pretty advanced in fighting the grey market (for example, I read Chanel is now using custom molecules to identify fragrances destined for different export markets - the invisible ink serial numbers were too rapidly found and copied).
But the UK MSRP just dropped 10%. I'm looking forward to see how fast the MSRPs will adjust.