Are statutory or other defences to be considered at every state of enforcement to preclude the act’s status as a crime?

Question

Are statutory or other defences to be considered at every state of enforcement to preclude the act’s status as a crime?

For one example, criminal Justice act 1988 makes it an offence to carry a weapon while providing a defence that it is used for religious reasons. If it is reasonably apparent to everyone involved that Jagmit is carrying a knife for its symbolic religious purposes (a kirpan), does this fully negate the status of his conduct as an offence? Or does that still have certain consequences and legal significance notwithstanding that his defence will certainly be able to stand up in court?

Is the defence only relevant at the court stage, or has he, given the applicability of the defence, not committed any offence at all? In that case, he shouldn’t ever even be arrested by police. Similarly, public order offences often have a defence that the utterances were within a private dwelling and couldn’t reasonably be expected to be heard outside of it.

Answer 1

canada

The existence of a defence is relevant, to various degrees, at every stage of the arrest and prosecution.

As an example, the self-defence provision in Canada starts with: "A person is not guilty of an offence if..."

If the circumstances meet the criteria for self-defence, then the person did not commit an offence.

At the arrest stage, absent a warrant, an officer needs to believe on reasonable and probable grounds, that the person committed or is about to commit an indictable offence or whom he or she finds is commiting an offence. That must take into account information that would inform whether a defence would be available. However, at this stage, the officer is not expected to have conducted a full or conclusive analysis. "Reasonable and probable grounds" is much lower than the "beyond a reasonable doubt" standard by which the defence would have to be disproved at trial by the Crown. It is even lower than the civil standard of balance of probabilities.

As the Court of Appeal for British Columbia said:

This standard does not require an officer to satisfy him or herself that there is evidence of proof beyond a reasonable doubt or even a prima facie case. All that the officer must have is an objectively reasonable basis for believing the suspect is presently in possession of marihuana, without necessarily ruling out potentially innocent inferences, defences or lawful excuses. ... There is no merit to the appellant’s argument that the officer was required to rule out potential innocent explanations before it could be said he had reasonable grounds for the arrest.

There are many permissible arrests in circumstances where there is ultimately a successful defence.

Similarly, while the decision to prosecute in Canada is nearly completely free from judicial scrutiny, every jurisdiction follows an internal charging policy that considers whether there would be a "substantial likelihood of conviction" (or similar threshold). This includes consideration of defences. In British Columbia, for example, the charge assessment guidelines direct prosecutors to consider any defences, or other legal or constitutional impediments to prosecution, that remove any substantial likelihood of conviction. If there is a defence that appears strong enough at this stage to remove a substantial likelihood of conviction, prosecutors have been directed to not bring a charge. And if, after bringing a charge, facts emerge after prosecution that change the initial assessment, prosecutors have been directed to drop the charge.

Answer 2

switzerland

In particular regarding weapons, the law makes the destinction between "Weapons" and "dangerous items". Dangerous items are objects that are dangerous, such as large knifes, a large crowbar or a baseball bat. These items are obviously suitable to harm someone, but they also have legal uses and they're rather common. (Well, maybe not the baseball bat, because that's not a very popular game here).

For buying, carrying or using weapons, a large number of regulations apply, generally requiring authorization and a formal declaration of the use case. Dangerous items, on the other hand, can always be bought or carried when one has a plausible explanation for doing so. (Art 28a of the above law) Carrying a baseball bat in your sports bag, together with a glove and a team dress would probably not cause any suspicion, however if you carried one under your coat on Saturday night in a pub, your excuse should be well prepared.

If you are arrested with a dangerous item, you can always try to argue that you intended to only use it for it's legal purpose. It will be up to the court to decide whether they believe you.