Approached by someone doing a “tourist survey” in Hoi An

Just putting this out there. My partner and I were approached today in Hoi An by a girl who told us she was a student doing a tourist survey and would we mind answering a couple of questions for her. We thought we would be nice and do it for her and she asked us where we were from and what our favourite thing was about Vietnam etc. she then brought over her colleague who said he works for the government and was helping with tourism and then said he had a “prize” for us for participating. He gave us a card to tear open and my partner won a hat which he gave him and then I opened mine and it said I had won the “best prize” which said I would receive an iPhone, a cash prize or seven nights accomodation at a selection of hotels in different countries. The girl was thanking us immensely because she now gets to receive her “salary” because I had won this ultimate prize and if I claimed it, she would get paid. Immediately we knew we had been suckered in to something and told them we weren’t interested and walked away. The guy was telling us we just need to go in a taxi to their office to claim our prize. Upon researching it back at the hotel we saw this is to get us to purchase time shares. Pretty annoying, just letting others know!