I hear that British travellers to the USA are being urged to check their passports. Presumably things to watch out for are visa stamps for places like Afghanistan or Syria, a first name along the lines of "Mohammed", the words "al" or "bin" occurring anywhere in your name, or a well-known human rights lawyer listed under "Person to contact in case of emergencies." However, officially all you have to worry about is whether your passport is machine-readable. This may be scant comfort for Cat Stevens / Yusuf Islam, but after that terrible album for Bosnia, I have little sympathy for him. Not that I was ever a great Cat Stevens fan - I think wherever he goes, they should play "Buddha and the Chocolate Box" just to embarrass him.