It will also risk turning neighbour against neighbour.
But it also sends out the wrong message that cannabis is a dangerous drug.
Firstly, cannabis is a plant - a plant that grew wild until about a century ago - a plant used throughout history since the times of the ancient Chinese and Egyptians right through Culpeper's Herbal time until the present day - and used widely for medicinal benefit.
Today it is used to treat, ease and cure a wide range of ailments and pains, from MS, epilepsy and glaucoma to headaches and back aches and even said to cure and ease cancers and tumours.
The number of users - often young people - that suffer bad consequences is a minute proportion of users - far smaller in number than those that get bad effects from using prescribed drugs. And in fact cannabis is prescribed in the raw but irradiated and standardised form of Bedrocan in many countries, and in the UK and elsewhere as a powerful whole-plant extract in alcohol (a far more dangerous drug itself) called Sativex.
Those youngsters that get cannabis do not grow their own, they buy from the street dealers just like adults - dealers that are untaxed, unknown, uncontrolled and may have few or no scruples about age or quality and may even offer harder drugs.
It makes no sense to punish all growers or users because a few users suffer - no more sense than it would to punish all drinkers because of those that suffer or do harm.
To solve whatever cannabis problems we have it is essential, as they realised in Colorado, Washington and the Netherlands, Uruguay etc, to allow adults to buy cannabis and to allow people their Right to their private lives including the growing of cannabis for their own uses.
PSNI 'scratch and sniff' cannabis plan: UTV, 27 September 2014
The PSNI is to distribute scratch and sniff cards to the public in order to raise awareness and improve detection of illegal cannabis factories.
The campaign comes after an increase in the number of cannabis factories discovered in the past year rose by 44%.
Since April, police have uncovered 49 factories. In the previous year they broke up 130 facilities compared to 90 in 2012/13 financial year.
The scratch and sniff cards contain an element which replicates the smell of the plant being grown, which is different to the smell of it being smoked.
It's hoped the campaign, launched by the PSNI and independent charity Crimestoppers, will educate the public on how to spot the signs of an illicit operation in their neighbourhoods and encourage them to report their suspicions.
A special presentation will also be made to landlords and others about the signs to look out for and a special DVD has been produced for further guidance.
Assistant Chief Constable Drew Harris said: "More than two cannabis factories are being uncovered every week in Northern Ireland. They are illegal and they are dangerous.
"The money generated by them runs into millions of pounds. That's money going into the pockets of organised criminals - used to fund even more criminal activity.
"From 1 April 2014 until 31 August 2014, police have arrested over 1,110 people for drugs offences and removed an estimated £3.9m of drugs from our streets.
"Over the coming weeks, officers across Northern Ireland will be distributing scratch and sniff cards to the public so that they will be able to recognise the signs and smells of cannabis factories in their local communities.
I have been impressed with this project and hope it will prove to be a successful additional tool to the police in their efforts to thwart cannabis growing in Northern Ireland."We know that people may not realise that the empty, run down house or flat on their street with people coming and going may actually be a cannabis factory. It's not just the stereotype of the remote rural dwelling or disused industrial unit."
Justice Minister David Ford
Justice Minister David Ford described the campaign as a "novel approach to a growing problem in society".
The Alliance minister added: "The distinctive smell is a tell-tale sign which the public should report to the PSNI or to Crimestoppers.
"This initiative is a very innovative example of law enforcement agencies, the voluntary sector and the public coming together to help keep Northern Ireland society safe."
Val Smith, vice chair of Crimestoppers Board Northern Ireland, emphasised the important role which the charity plays in crime detection: "It is really important for people to understand what happens when they ring Crimestoppers.
"There is no caller ID, so the person taking the call can't see the phone number that the call is being made from.
"This means that the caller remains totally anonymous. Similarly, the Crimestoppers 0800 555 111 number does not appear on your telephone bill, a further measure that helps to ensure complete anonymity.
"The caller isn't asked for their name or any personal information; they are simply given an opportunity to share information that they may have about an incident or suspicious behaviour.
"Any information Crimestoppers receives is then submitted to a central point within the Police Service of Northern Ireland and forwarded to the relevant policing area. This information can result in searches being conducted which lead to drugs being seized or cannabis farms being closed down."