Visitor Visa - B2

MY mother went for an tourist visa interview on 18th Nov and she had all the paper work (That we can think of and all help to this website as we collected most to all of them mentioned on thsi website). She was applying alone as she is widowed and I am here with my wife. The CO didnt asked any (Even a single doc neither the invitation letter) and just ask basic 3 questions like:
Where and why are you going, who lives there, what does you son do and before she would reply to third question with the company name, he said thoose golden words Your Visa is Approved and she will get in mail. Sorry for writing the review late. She had the interview in Hindi.
But just to mention it, dont take it so lightly as my mom told me there were lot of people before her, for whom the CO asked a lot of papers and also there was a lady whoose visa was rejected and she was literally crying in front of CO saying my son and husband is there, i have everything . please do something. so well it is easy but not that easy!!! Sorry again for writing experience late!