Upvote:2
Well, technically, you have another option: travelling to Macao (or any third country)... But yes, her only option is to do so.
If you fly to Taiwan from the mainland, the Chinese immigration control will ask for a Taiwan Travel Permit issued by mainland Chinese authorities and a valid exit visa recorded on the permit. If you don't have both of them, you cannot travel to Taiwan from mainland China as a mainland citizen. However, no one really cares if you travel to Taiwan via a third location (that is to say, unless you are suspected of espionage or anything like that). If you travel via Hong Kong then you're fine.