Authorities in London cracked down on prostitution ahead of the 2012 Olympics and police in Vancouver made some efforts to curb street prostitution and petty crime before the Winter Games two years earlier.
Major international sporting events also heighten alarm over possible sex trafficking, with observers often predicting a massive influx of trafficked women to meet an alleged increase in demand for commercial sex.
The executive director of Maggie's, a Toronto organization run by and for sex workers, says fears over potential trafficking during sports competitions are typically overblown and sometimes serve as excuses to round up local and foreign sex workers.
Jean McDonald says she worries a stronger police presence could have a "harsh impact" on street-based sex workers, who would be forced to work in more isolated — and potentially unsafe — conditions.
Advocates for sex workers' rights have long argued that isolation exposes sex workers to harm and violence, and have pushed for the decriminalization of sex work.
A spokesman for the Integrated Security Unit, which is responsible for security for the Games, says authorities are focused on keeping Ontario residents, visitors and athletes safe.
Ontario Provincial Police Sgt. Peter Leon said the ISU is aware of "issues" surrounding the Games but would not say whether sex work or trafficking are a particular concern.
"With respect to cracking down...that's operational and that's something that law enforcement can't really answer," he said.
With hundreds of thousands of people expected to come for the Pan Am and Parapan Games in July and August, some officials — including the head of the Canadian Council of Churches — are predicting a boom in sex trafficking to the region.
However, a study examining the impact of the Vancouver Olympics suggests there was no significant influx of sex workers or reports of a spike in trafficking there.
The survey of sex workers found there was less demand for their services, possibly due to the difficulty in meeting clients.
"The Olympics period remained statistically significantly associated with perceived heightened police harassment of (sex workers) without arrest, decreased availability of clients as well as increased difficulty hooking up with clients due to road closures/construction," the University of British Columbia researchers found.
"Police harassment/crackdowns can displace outdoor sex work markets to more isolated spaces away from health and support services and increase risks of violence and transmission of HIV/STIs."
Few studies have attempted to measured the scope of sex trafficking during large sporting events.
Quantifying it "has proven to be elusive given the clandestine nature of the industry," according to a study published last year in the journal Public Health.
"It almost certainly exists, but to what extent is the big question. It is a hidden problem on a global scale in plain view with tremendous public health implications."
A report by the Global Alliance Against Traffic in Women, meanwhile, argued there is a wide discrepancy between claims made before events and what actually occurs.
"There is no evidence that large sporting events cause an increase in trafficking for prostitution," the organization said.Suggest a correction