Warning. If "friendly young Chinese students" ask you to take their photo, then take yours, and indulge in earnest chatting, expect this to lead to an invitation to something like a "tea festival". At the end you will be faced with a bill of hundreds to thousands of RMB. Although you will probably be able to "haggle" this down, it will still end up as a complete rip off. As you are in "their territory", there is little you can do at this stage other than pay up and get out.
Advice. If approached by "friendly students", walk away. A pity we didn't. We are now RMB 2000 the wiser.
We were accosted in People's Park near the metro. Apparently a common location for this sort of thing.