There are other provisions in section 530 and section 530.1 that use similar language. Some more specific language was at stake in the Beaulac case, which was “if the administration of justice warrants it”. Whatever the phrase is, the Supreme Court has stated that the courts would interpret these discretionary powers in the code with a view to implementing the basic right of the accused to a trial in his or her language.
So we have guidance on what the types of circumstances there might be, but it does open up this section to some interpretation. In the original amendment, “may” and “per” would have developed according to case law as well.