I cannot see how this could possibly work on the return journey. At check in for the return flight, which happens in EU2, the airline is responsible for collecting all the information required for the EU1 to USA flight, and this information is transmitted to the USA. The information is transmitted electronically and includes passport details. It's possible that Fred 2 (whose information is what the USA receives) could get away with this - he's a no-show and so the US just shrugs its collective shoulders and isn't concerned when Fred2 next visits. However, how will Fred1 explain why he has no APIS information on file when he arrives. He'll almost certainly get sent to secondary, even if he is a US citizen, and then the story will start to unravel. Travelling under a fake identity is taken very seriously across the Atlantic.