But rights groups say problems remain. "Violent forced evictions in China are on the rise as local authorities seek to offset huge debts by seizing and then selling off land in suspect deals with property developers," according to an October report by Amnesty International, called "Standing Their Ground."

The 85-page report also said there is ineffective redress for Chinese citizens like Xie and her husband, who - without cash to hire legal help - petition the central government directly with local grievances that range from allegations of illegal land seizures and forced evictions to corruption and abuse from local authorities. They often face weeks or sometimes years of forced detentions without charge, human rights groups say.

"From our research and research from domestic Chinese human rights [groups], they are held from a few days to several months and routinely subjected to physical abuse, sleep deprivation and very often they have to buy their way out of custody," Kine said. "The government has denied there are any such black jail facilities in China. Even though [Chinese] state media run stories about black jails, there is an official disconnect."

Baber at Amnesty International said it is hard to quantify the number of people who are detained illegally in China, but "it is a large phenomenon," she said. "Just from the volume of people who put their energies into pursuing petitioning and continue to do so. It will be a large problem still."

Petitioner: Kept under guard

Xie said there were several guards posted outside of her Holiday Inn Express room and two women who were living in the room with her whose job was to monitor her.

She said while held at the hotel, she was told she would be given "classes about petitioner regulations." But there were no classes, she added. Xie took a reporter to the hotel to show where she was allegedly detained. The rooms were neatly furnished, with a flat screen TV and abstract art hanging on the walls.

When the front desk worker was asked whether they were aware people had allegedly been held against their will in the hotel, the employee said there were a number of guests who were staying in their rooms and were not leaving, and there were people standing outside their room, but that they had no idea why.

IHG said they interviewed all employees at the hotel in June after being first contacted by CNN, none of whom confirmed this story. A review of hotel security tapes was impossible, the hotel said, because recordings are erased after one month. The hotel had the employees sign affidavits attesting to their version of events, a hotel spokeswoman said.

"IHG is committed to operating our company with integrity and we have a Human Rights Policy applicable across the business. We have signed up to the UN Global Compact, aligning our operations and strategies with the ten universal principles that include commitments to human rights and labor standards," IHG said in its statement. "Our staff is trained to handle different situations and were a situation to arise, our staff would report an incident to the relevant authorities and IHG."

China has become a leading market for the InterContinental Hotels Group, which owns the Holiday Inn Express, Intercontinental and Crowne Plaza brands. Greater China led its first half, with a 9.7% increase in revenue per available rooms. IHG, headquartered outside London, generates revenue from 181 hotels in greater China, with plans to open 160 more hotels, according to the company.

IHG's local partner in the hotel is Shanghai Harbor City Hotel Investment and Management Co.-- a subsidiary of Shanghai Harbor City Development Group. Like most of IHG's properties in China, a local partner legally owns the hotel but IHG manages the property. Zhu Gang, a manager with Shanghai Harbor City Development, said the company "knows nothing about" people being detained at the Holiday Inn Express. "No violence happened in the hotel," he said.