'Twas the night before Christmas, there was a cleaning of house...illegal foreign teachers were nestled all snug in their bars, when across Shanghai there arose such a clatter...more rapid than a phoenix the police came, they shouted and called the expats by name...

According to firsthand accounts posted on various expat forums on Christmas Day, at least 50 foreigners were rounded up by Shanghai authorities during a Christmas Eve sting operation to catch expats working illegally in the city. Wannabe teachers were allegedly honeytrapped with a too-good-to-be-true ad for 20,000 yuan ($3,035) a week.

The ensuing arrests and deportations - supposedly 20 of the 50 did not have proper visas - were warranted and I won't be shedding any tears, as this sort of sting has been long overdue here. This city has in recent years become flooded with destitute foreigners from around the world seeking jobs. The relatively high wages for ESL teachers (minimum 200 yuan per hour) and an abundance of unlicensed teaching centers are temptations too easy to resist, turning Shanghai into a migrant magnet.

I can speak on this personally, as more than once I have been lured by lucrative though illicit job offers that could have gotten me tossed out of the country. A few months ago, in fact, I was asked by a Chinese friend if I would do some private tutoring for a group of adolescent Shanghainese girls.

The last thing I wanted to do after a long work week was wake up early on a Saturday morning to recite "the quick brown fox jumps over the lazy dog" for some spoiled kids, but at 600 yuan for just one hour, I admit I gave the offer some thought. According to relevant Chinese laws, foreigners are not allowed to work independently from the employer who officially issued their Z visa, which means I would have been jeopardizing my real job had I started tutoring privately on the side. So I had to say no.

Two years prior, however, I was not as quick thinking, only narrowly dodging the PSB's bullet. I was completing a short-term contract as the managing editor of a Shanghai expat magazine and had time remaining on my one-year Z visa when an HR agency told me about a teaching position - 10,000 yuan per month just for working a few hours on weekends for a prominent English training center chain, the largest in Shanghai.

I went in on a Thursday for a training session at their skyscraper headquarters behind the Xujiahui metro station. At the time I was unaware of an Exit-Entry Administration of Shanghai Public Security Bureau policy that forbids foreigners from working for a new company on an old visa. You are supposed to leave China within 30 days after your contract is over; those who don't will be slapped with fines as high as 10,000 yuan. The Chinese employer who interviewed me, Elaine, told me "mei guanxi" (no problem).

That same year, the central government released a series of new regulations on foreign teachers, stipulating that they must have at least five years experience as well as a TEFL or CELTA certificate in addition to a university diploma. I had all these things, but most of the other fellows I was training with - including a senior citizen from Israel, an Italian university student and some other white faces from unidentifiable European countries - did not.

I returned to the fancy office on Monday morning to sign my contract. But in a moment of only-in-the-movies perfect timing, literally as I stepped out of the metro station I received a text message from a friend who also happened to work there alerting me that, over the weekend, half of that chain school's 50 foreign teachers had been arrested in a PSB sweep covering 20 branches.

As it turns out, the company had been illegally hiring foreigners on tourist visas. Because of the high turnaround rate due to unpleasant working conditions at all their branches, rather than keep paying for expensive work visas for foreigners who in all likelihood would quickly quit, the company tried to save money. Many teachers were fined and deported, and Elaine, the Chinese lady I was supposed to sign my contract with, was also arrested for telling the teachers to lie to the police by saying that that they were giving "demo classes."

I noped out of that contract despite the dozens of calls I received from the company in the following days begging me to come back and sign (they no longer had enough teachers to cover classes the coming weekend). But I can see how easy it is for naive, newly arrived foreigners in China to get sweet-talked into an illicit work contract by a school.

Unfortunately, the burden is on us to be informed of China's constantly changing regulations, but for those foreigners who attempt to skirt the system by teaching here without a Z visa, I hear Chinese jail is a nice quiet place to work on your lesson plans.

The opinions expressed in this article are the author's own and do not necessarily reflect the views of the Global Times.