Here is one author's experience (note in hindsight this author admits to being foolhardy, and doesn't recommend such exuberant curiosity, although, wink wink, whats the fun of travelling without a few risks!):
My first day in Jaipur, I was wandering the bustling streets, when out of nowhere a young fellow rode up next to me on his motorbike, with a cricket helmet and orange sunglasses. He introduced himself as 'Bapu', and immediately started to accuse Westerners of hating Indians, and not wanting to associate with them or get to know them, but only to see the historical sites and leave.
Naturally in the backpacker's spirit i rejected this, and so he offered that we go discuss this over a cup of tea. Being an experienced traveller, this set off warning signals, but i was in the mood for adventure. I rode on the back of his motorbike to a local, dark out of the way restaurant. I quickly refused to drink anything, as i had heard of such ploys where the tea would be drugged, and i would wake up with all of my posessions gone. He soon lost interest, and i left. Later that day, another youngster attacked me with the same argument, and offered to discuss it over tea; naturally i refused (i heard later from another traveller that he had accepted an invitation, and suddenly a policeman arrived and arrested the youth, and advised him of the scam).
That evening I went to see a movie at the Raj Mandhir Movie Theater. While waiting in line (where people were pushing and shoving to get tickets), a youth approached me and asked me to buy him a ticket as well. I did so, and as it turned out we sat together in the theater. Now if you are going to Jaipur, I highly recommend seeing a movie here, it is a positivly astounding experience. The audience talks during the entire film, and shouts, claps and cheers; the movies themselves are beyond belief, usually rife with dancing and singing, and often copied scene by scene from popular Western movies!
This young fellow invited me afterwards to go to a party at his boss's house. Having little else to do, i hopped in a car with them and went. We got to this house, and no sooner had i walked in the door, than who did i see lounging on a couch? Bapu! He didn't say a word for a good 15 minutes, and then stumbled through an explanation. I was willing to forgive, and talked to the fellows for a while. Later, the 'boss' came in, and we talked, and he invited me to come for tea the next day at his office. I agreed, and he sent his friends to drive me back to the hotel. As we drove back (a little tipsy i must admit), suddenly a jeep crashed into the side of the car! Luckly nobody was hurt, but the car had been hit pretty bad. The fellows ran over to the jeep, and ran back saying 'no problem! its the police, we know them'.
The next day they picked me up to go to this boss's office, which was in fact a jewelry store. We casually talked for a bit, then he proposed that I assist him in smuggling jewelry to the US. Essentially, he reasonably explained that every tourist has a quota of several thousand dollars of untaxable exports. I, being a poor backpacker, naturally had only around 100 dollars worth of shawls, etc, to bring out. So he wanted to send a package by post to NYC in my name and under my export quota. When I arrived in NYC, a man would take me to pick up the package, and hand it over, and get 15000 dollars cash. A very attractive offer, but i had read about such scams and denied. He tried to convince me (i was clearly torn by the desire for $15k), but finally i said no, and he did little to stop me. Having almost gotten drugged, scammed, and killed in an auto accident, i realized it was time to move on. And thus I bought the next train ticket out of Jaipur!