It's definitely just a UK thing, because Rays has a number of UWG athletes on their open teams. I'm pretty sure Electric and Rust had to re-work some parts of their routine after the roster for Team U.S.A. was announced, because a number of Electric and Rust members couldn't continue practicing with Rays two weeks before Worlds when Team U.S.A. practices begun. If it was just one or two athletes it's fine, but not having up to four or more members would mean not being able to practice the pyramid for two weeks going into Worlds.