The Trump administration’s hard-line approach to immigration is raising concerns among key allies and leading them to keep a closer eye on how their citizens are treated when they travel to the United States in the wake of recent detentions and deportations.  Germany updated its advice for travelers heading to the United States this week, underscoring that a visa or entry waiver does not guarantee automatic entry.  “The final decision on whether a person can enter the U.S. lies with the US border authorities,” a spokesperson for the German foreign ministry said.  But they also said that it did not represent a formal travel warning.