http://www.theregister.co.uk/2005/05/25/eu_bio_visa_trial/
John Lettice
"The slight snag with the single biometric identity document - as we've noted here in the past - was identified by Brussels' techies late last year. The technology is intended to use contactless chip technology, despite the obvious gotcha that it'll be perfectly feasible for unauthorised readers to lift data from your passport. But if you've got multiple travel validations using the same technology in the same passport document, having them all chattering at the same timed screws up the readers. As the techies reported last year, the original plan to have visas using contactless technology in a passport which itself uses that technology just plain doesn't work."
