Carrying a set of keys on a train could result in a police officer asking you to empty your pockets under proposed Queensland laws, a public hearing has heard.
Should they pass parliament, the laws will give police "exceptional" powers to search people for knives on public transport and in nightclub precincts without reasonable suspicion.
They will do so using metal detection wands, but a review following a trial on the Gold Coast found an increased number of drug detections linked to the searches.
How the use of a metal scanner was uncovering drugs was explained by Griffith University's Janet Ransley at a public hearing into the laws on Monday.
"Everybody has on them keys or a pen or some kind of metal object," Professor Ransley said.
"Once a wand has triggered, the person wanded is required to empty their pockets."
If the wand continues to go off, an officer can form reasonable suspicion and is entitled to a search.
"That's how we get the increase in drug detections," Prof Ransley said.
Care needs to be taken to ensure the powers don't result in the "by-passing of reasonable suspicion safeguards", the report by Griffith University's Criminology Institute noted last year.
"The ability to conduct wandings in the absence of any reasonable suspicion is a very significant departure from normal criminal law and procedure," it says
"While possessing drugs is an offence in Queensland, the impact of wanding on a person's human rights has been justified by the possibility of reducing violent crime, not drug offences."
Young people found with a small amount of drugs will likely experience flow-on effects through contact with the criminal justice system, Prof Ransley said.
"That's something that needs to be addressed, perhaps with training," she said.
The new laws will mean the wanding trial is extended for two years and expanded to all safe night precincts in Queensland, as well as public transport.
"Throughout the trial we have seen hundreds of dangerous weapons being detected and taken off our streets," Queensland Police Acting Deputy Commissioner Mark Wheeler said in a statement.
"There is absolutely no reason why a law-abiding citizen needs to arm themselves with knives, knuckle dusters or screw drivers as we have seen on the Gold Coast."
The parliamentary committee will table a report on the proposed laws on February 17.
