I'd like to clarify something here.
There are several different primary designated offences. For example, if the person is a member of a criminal organization, the onus is on that person to convince the court.
In the case of secondary designated offences, the Crown must make the request of the judge. The latter will decide, in keeping with the sound administration of justice and based on the person's criminal record, the circumstances surrounding the offence, etc.
That's how it works. There are three categories: the 16 most egregious primary designated offences, other primary designated offences and secondary designated offences.