The most memorable incident involving cheating goes back to middle school. I was in a paticular class where certain girls would cheat on quizzes 50% of the time, though that statistic has limited accuracy since I was usually paying more attention to the quiz than other people’s habits. Finally one of them got caught, and got a referral (the highest punishment short of suspension). She was crying because she was one of the girls who cheated less often and she kept on saying “— does it all the time and they didn’t catch her.” I had limited sympathy for her. It was unfair that they caught her instead of some of the others, but she should not have cheated either.
There are a couple of boys at my present school who are chronic cheaters. Sometimes they get away with it, and sometimes their schemes backfire. They are most successful at cheating P.E. hours. My high school (indeed all high schools in the city) require two years of P.E. A little less than a fourth of the students, myself included, get this requirement automatically fulfilled through dance and theatre classes. There are two P.E. classes availible for other students, but they can only handle 60 students a year (basically, a small percentage of the school). Therefore the majority of students have to fulfill the P.E. requirement through extracurricular activities. These chronic cheaters merely lie about doing their P.E. hours, and they get away with it because the administrators have more pressing matters to consider, and they certainly want an excuse to let these students graduate.
If you really want to curb cheating, give assignments which are difficult to cheat on. It’s difficult to cheat on an essay like “Write about a member of your family” (the essay must be in English, of course). If they copy each other, fail both of them (that’s the policy most teachers use if they see two essays which are too similar). You could make multiple versions of tests, make sure people who sit next to each other get different versions, and if anybody talks or moves during the test, fail them (another popular policy at my school).
Or you could just let them cheat. Ultimately, you get paid whether they cheat or not (especially if the administration does not care). They are supposedly taking your English class in order to learn English. If they decide to short-change their education by cheating, that’s their loss, not yours. However, if you take pride in being a good teacher, I can understand why you do not take this approach.
EDIT : When I was researching the Italian education system, I heard that cheating is much more prevelent in Italy than in the USA, and Italian and Mexican cultures definately come from some of the same sources. In the estadosunidos culture, we generally value honesty, quality, and integrety, and we certainly lump cheating among the enemy of those values (we don’t want doctors who cheated through medical school operating on our body). While I’m sure Mexicans value those things too, they do not connect cheating so strongly with the enemies of those values. From what I can understand of their culture, cheating is a practical way to get things done.