So I actually visited Chiang Rai/ Chiang Mai and Mae Sae 2 weeks ago (Northern Thailand near the Laos and Burma borders).

My wife is Thai, and along with our Thai tour guide, I was able to get a little insight/rumor on these people. I cant confirm or deny any of this, so take with a generous helping of salt.

The people I saw are from the Karen (Thai: Kareng) ethnic group, and most of them are originally from Burma having immigrated to Thailand a number of years ago. They have minimal legal status in Thailand, and supposedly every year each person is required to submit some sort of "documents" in order to stay in Thailand, and a fee of 10000 baht ($300US). Traditionally the tribe cultivated opium as a crop, which was halted by the Thai govenment back in the 1960's or so. This actually makes some sense to me, given that they are very close to the famed golden triangle (sandbar of no-mans land in the middle of the Mekong river famous for opium trading). As a result, the tribes now have engaged in the "tourist" trade as a way to generate income to cover their expenses.

Now it's certainly possible that these "fees" are really bribes; I have no way of knowing, but it being Thailand, that thought is probably closer to the truth. So I'm in general consensus with #7.

I have no idea on the issue about them wanting to leave and not being allowed as per the BBC article. It's certainly plausible; but I didn't hear anything of the sort 2 weeks ago. And the tribe certainly does live in a very mountinous and fairly isolated region; which gives them few prospects for the future, outside bussing more tourists (gawkers) to visit them.

I also do not know if other tribes (other Karen groups, Akha, Hmong, regular Karen, etc), have the same situation.

I can confirm the fee to see the villiage (as levied by the tour company) is 250-300 baht per tourist, as noted by Daniel above, and the BBC article.

I didn't get the impression that the women were forced (as in forced freakshow) at all, in fact, my wife and I had a lot of smiles and a pleasant exchange (in Thai) with the grand-mother who offered us betel paste (which we declined). According to our tour guide, the Karen women actually run the village, and have done so for many generations as the men often were "distracted" by partaking of too much opium. Certainly the women are the current income generators. But obviously I was on the outside looking in, I have no way of knowing the true nature of this, but to me it seems more of "lets get some easy money from tourists" (not so different then, say the Jim Rose Circus) then some sort of forced situation. But given that this is SE Asia, it could be either, or possibly even both.