They say that because in St Thomas, the "shopping area" is in the port facilities. There is about a 1/4 mile of shopping (much like an outdoor mall) next to the ship. If you walk all the way down to the end of the shopping area you find the entrance to the port. You can also find taxis and such there. So after your tour, the bus will drop you at the entrance, you show you ship card and then walk to the ship. Its fairly safe since most of the people are passengers.
Also, most of the stores in this area are repeats of the stores in the downtown shopping district. Many people prefer to shop downtown for the ambiance.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007