I know, that Switzerland and Liechtenstein are not members of EU. However, they are members of Schengen. Schengen rules remove all internal border controls between member countries.
If I travel to Switzerland, must I take my passport with me, or would it be enough to have my personal ID of one of EU countries?
Inside Schengen Area, I don't expect to be stopped for border control. But police can control a car anywhere, and possibly, this is where I might need passport instead of ID.