If you go to a foreign bank for tax, interest or other benefits you are exercising a high degree of financial autonomy, choosing a banking system to be a part of. It's not a default decision by someone who needed somewhere to deposit their £438 per week salary. I really don't think you can make the same argument about guaranteeing deposits in these cases, especially without a (low) cap of £10,000 or so.
The Bank of England bailout transferred money from future middle class workers in the UK to wealthy and upper-middle class people, maybe 2 generations apart. I think it was immoral.