If you are involved in getting a drug from its source to a user you are trafficking. Trafficking includes manufacturing a drug so it can be sold, exchanging drugs for something else or even just offering to sell a drug to someone. Even if the substance turns out NOT to be an illegal drug, so long as the would-be seller thought it was at the time of offering it for sale they may be found guilty of trafficking. Likewise, in relation to 'rip-offs' - where a person passes off another substance as a drug (e.g. aspirin as heroin), or does not actually intend to provide any drugs (e.g. they take the money and run) - they may still be found guilty of trafficking.

Trafficking also includes buying drugs for a friend, even if you do not make any profit (e.g. you buy cannabis for $30 and sell it to someone for $25 as a favour). You don't have to be caught with a large amount of a drug to be charged with trafficking. The police may charge you with trafficking if you have packaged the drug for sale and have items such as scales and cash on you, even if the amount of the drug found is less than what the law calls a 'traffickable quantity'.

If you are caught with a 'traffickable quantity' then it will be up to you to prove that it was not for trafficking. Since 1997, when drugs in powdered form are weighed it is now the weight of the whole mixture that is considered, not just the weight of drug in the mixture.