The police system in Thailand works a little differently than that at home. The government pays their police force very little and the community becomes responsible for supporting the police financially. Police in Thailand are commonly known as the BiB (boys in brown) due to their uniform.
For most tourists this will have no consequences for them but you should be aware of how things work should something happen. This could save you some time and frustration.
If you find yourself being talked to by a police officer in Thailand you should be aware that trying to convince him that you have done nothing wrong is pointless. It is better to be humble, smile a lot and cop what is coming. With a bit of luck what you have been caught for is minor (eg not wearing a helmet on a motorbike) and the problem can get sorted quickly.
In most cases small problems can be sorted quickly and you will have two choices. You can get a fine from the officer and you will have to go directly to the station and pay up. The easy way is to leave the fine in the care of the officer who you are talking to. This can save you a lot of time and hassles at the station.
If you have done something more serious it will take longer and may result in you spending time in the monkey house (ie jail.)
There are three things that will almost definitely cause you a lot of problems and will highly likely result in jail time: under-aged ladies, drugs and visa overstays.
As far as a foreign man is concerned the age of consent in Thailand is 18. For a Thai couple it is less but that is irrelevant.. Also remember that a lot of countries can prosecute their residents for crimes committed overseas. Don’t come to Thailand if you are not prepared to abide by this law.
Being in possession of drugs is not smart in any country and even more so in Thailand due to the stiff penalties and the jail system. Also be careful with who you have in your room. If you find a lady has drugs get her out as soon as possible as you may be held responsible purely because you have more money.
Many people overstay their visa and have no problems. However, stories of people getting caught by the BiB on overstays is not uncommon. If caught you will spend time in jail (maybe a week) before you are deported at your expense. You may also get a nasty stamp in your passport. There is no need to overstay in Thailand.
It is a legal requirement for a visitor to be able to produce a passport on demand. Technically this means that you should carry your passport at all times. For obvious reasons not many people like to carry their passport while they are out drinking having fun. You can carry copies of your passport details page and the page containing your visa/entry stamp. It is not guaranteed to prevent the BiB causing you some inconvenience but it is better than doing nothing.
A first time visitor with very little knowledge may well be shocked by this but prostitution is illegal in Thailand. Yes it is everywhere on open display but that is one of the great things about Thailand; there are many conflicting situations. Likewise pornography, sex toys and abortions are illegal in Thailand.
Even though gambling is common in Thailand it is illegal. Again stories of people getting caught gambling are not uncommon.
The supply of medication requiring a prescription without a prescription is illegal in Thailand. However many drugs, but not all, are available in pharmacies in Pattaya. Erectile deficiency drugs come under this category. Many pharmacies will sell you both the original product and their generic alternatives. Most people find the generic brands as good as (and much cheaper than) the originals product. For generic Viagra ask for Kamagra and Cialis is Apcalis. Don’t use these drugs if you have any sort of cardiovascular problem.