Another day, another Dubai conviction for an expat for "indecent behaviour". Yesterday, a British woman and Irish man were sentenced to three months for "breach of honour with consent" (that's "sex" to you and me), fined for public intoxication, and scheduled for deportation after their sentences are served.

The annals of Dubai's court are replete with stories of expats who have fallen foul of decency laws. Britain's tabloids are regularly incensed by the "barbaric" arrest of hapless British expats who'd just had one too many, or made the cultural faux pas of being physically intimate with a member of the opposite sex in public.

The newspaper The National has made an institution of court reports from the UAE's "moral trials". Reminiscent of Dickensian tabloid court journalism of crimes of passion, sexual intrigue and political scandal, the stories that regularly stem from these cases are a mix of humour and melancholy, displaying not only the farcical lengths to which plaintiffs go to deny their crimes, but also the bleakness and isolation endured by expats in a land where the cultural terrain is bewildering.

The deadpan trial dispatches are often inadvertently (or perhaps deliberately and skillfully) droll. The first report on the couple convicted yesterday began with "a drunk Irishman accused of having sex with a British woman in the back of a taxi was caught with his trousers down, a police officer told a court today". In one of the more recent cases, the report starts with "a man returned to his apartment to discover one of his two wives in bed with another man, a court heard this morning" (which immediately suggests to me that the wife was merely claiming her right to two partners as well, and that this seemed only fair, as it restored some symmetry). The report goes on to reveal more bizarre details. The husband shot the other man with a taser gun, while the wife maintained that her alleged lover merely fell asleep, but that "she did not know why he took his clothes off". The forensic detail doggedly pursued in these cases is also surreal. When presented with the damning evidence of a used condom, the lover admitted that it was his, but that he merely masturbated into it. The couple also admitted to consuming alcohol. What did the aggrieved husband do when vindicated by all this damning evidence? Dropped all charges of course.

There are also tiers of trials falling, like much in the Gulf, along nationality lines. Westerners generally find themselves on the wrong side of the law due to alcohol consumption and the resulting blurring of the lines between what is acceptable behaviour in private and public. Locals are also more adept at negotiating the country's laws. With cases that involve Arab nationalities, it is often the case that a disgruntled or wounded individual has reported the case to the police and is seeking redress of a personal slight in a public court. It's handy to be able to report your partner to the police when they cheat on you.

In a minority of cases, Emiratis are caught on the wrong side of the moral law. Earlier this year, a man was convicted for attempting to blackmail two women into having sex with him by threatenening to make use of "indecent photos". In a victory for the women, the accused was sentenced to three years. But in a surprising turn of events, the women were foiled and sent to jail for three months – for having consensual sex with him in the first place (which is, of course, how the man got the incriminating pictures).

The tragic-comedy displayed in the country's courts is a fallout of the extreme diversity of nationalities and values present in the UAE. Expatriates – 60,000 of whom are Britons, outnumber Emiratis – and the co-existence of clashing cultures is often an uneasy one. Time Out Dubai caused uproar this year when it issued a list of the five best bars in which to drink during Ramadan – islands of permitted debauchery in a sea of conservative rigour. Dubai, and to a lesser extent Abu Dhabi, are among the most accommodating of expats' liberal lifestyles – but the trade-off is that they are among the most intolerant if these extraordinary freedoms are seen to be abused.