The EU's new Entry/Exit System (EES) is causing chaos at European airports - and three countries are already starting to opt out. Greece has suspended the system until September. Portugal and Italy are preparing similar moves ahead of the May school holidays. Spain, France and Croatia could follow.

The problems are concrete: the biometric technology doesn't work properly, there aren't enough border officers, and queues at passport control stretch for hours. Passengers are missing flights. EES requires biometric data - facial scans and fingerprints - from every visitor who is not a Schengen citizen. In theory, it sounds neat. In practice, it has produced gridlock.

Tourism analyst Seamus McAuley sums it up: "Countries are not going to sit on their hands and watch Greece pull in their tourists just because passengers don't run into EES-style misery there. That would be a political catastrophe."

For the Balkans, this story is directly relevant: citizens of Macedonia, Serbia and Bosnia travel to the EU on biometric passports but without Schengen status - which means EES hits them directly. Long border queues are not breaking news for them. The difference now is that everyone else has noticed too.