OrphanCrow : Scratchme, Hong Kong has a history of street vendors that is not seen on mainland China.
If you visit the PRC, you will find that street vendors are quite common. I've had 12 or more visits since the year 2000, and every visit, and in many cities I've noted street vendors. Food may be the favourite item, but clothing and household items are also common, as are things like shoe repairs, bicycle repairs and even clothing repairs, once saw a woman with a treadle sewing machine repairing clothing- all on the street.
\Just last night I watched a Chinese TV show on Australia's SBS called and one of the contestants described how he had made a lot of money through street vending.
On the other hand I know that there can be some harassment, but that could be related to the possibility that its possible that in some areas they need a city licence.
The reason there are no witness carts on Chinese streets, is that JWs do not have legal recognition*, so no 'legal' meetings or activity. ( NB. They also 'banned' in Singapore**)
* See: http://www.refworld.org/docid/45f147082f.html
** Quote: "In 1972 the Government deregistered the Singapore Congregation of Jehovah's Witnesses on the grounds that its existence was prejudicial to public welfare and order because its members refuse to perform military service (obligatory for all male citizens), salute the flag, or swear oaths of allegiance to the state.At the time, there were approximately 200 Jehovah's Witnesses in the country; as of 2007 there were approximately two thousand. Although the Court of Appeals in 1996 upheld the rights of members of Jehovah's Witnesses to profess, practice, and propagate their religious belief, and the Government does not arrest members for being believers, the result of deregistration has been to make public meetings of Jehovah's Witnesses illegal." (See - https://en.wikipedia.org/wiki/Freedom_of_religion_in_Singapore) The reasons for the PRC ban are likely to be similar.