Unfortunately, I suppose this is exactly what we (meaning the electorate who voted since 2001) wanted. By allowing politicians to pass bills like the Patriot Act (which started this whole mess and quickly brought about similar security and surveillance laws in at least every other country that's on friendly terms with the US) we brought this kind of treatment on ourselves. How can one establish organizations like the TSA or the Border Force - its UK counterpart - and seriously not expect things like this to happen?
Unfortunately, the majority likely doesn't care at all when some 'snotty' designer gets held up at the airport and sent back to her home country. "Probably deserves it anyway in some way, doesn't she?" In fact, resentfulness towards people who get to 'live the life' and travel for 'work' might play a role here, too.
The aspect of a German company paying her in British pounds. shouldn't be a problem at all. After all, that's what the EU single market should be about. Theoretically, that is ... It seems as if the EU can't get anything right anymore these days, though.
Just claiming VAT you payed in another EU country has become so ridiculously complex I have given up on it. Fortunately, in my case it's just things like the occasional conference fee so the loss is minimal but I can't imagine how anyone could run say an eCommerce business in Europe and sell in more than one EU country these days without having to resort to founding a company in each of those countries.