Well, after a many e-mails and much conflicting advice about the availability of a Visa at the border to visit the Shenzhen Special Economic Zone on a day trip, the following is what I consider to be the definitive, accurate advice. It comes from someone I met on a CO flight from GUM to HKG who is based in HKG and who is a high official of the Kowloon Canton Railway Corporation.
=====Dear Ed
You will never get the same answer twice but I have taken USA passport holders a few times. Yes, you can get one at the Lowu border for HK$100 (but not all countries are eligible for this instant visa). Clear HK Immigration and cross the bridge to the China side. Stay to the left and take the escalator up to 2/F (everyone else will be going straight). Go into the office and fill out the forms on the right side and give the officer your HK$100. It will take a few minutes depending on the number of people. Then, go out to Chinese Immig and fill out the Arrival card while you wait in line.

Your daughter IS SURE to go wild in the Commercial Shopping Center just across the bridge outside of customs. There are good tailors inside the building with all the name brands cheap. Tell her Prada purses are about US$12 to give her an idea and Nike sneakers about the same========================================