Sheila Lim, 25, travels from Singapore to the United States every year to spend Christmas with her boyfriend and his family in California, usually staying for nearly a month.She has never had trouble entering the country, but on her most recent trip she noticed immigration queues moving more slowly than before.“This November, I waited two hours in line,” Lim told This Week in Asia.That experience has left her uneasy about a new US proposal that would require visa-exempt travellers to submit...