Litigation Guideline #14: Limitations and equitable defences should be pleaded only where there is a principled basis and evidence to support the defence.

Extinguishment, surrender, abandonment

The Principles discourage certain long-standing federal positions, including relying on defences such as extinguishment, surrender, and abandonment

Generally, these defences should be pleaded, only where there is a principled basis and evidence to support the defence. Such defences must not be pleaded simply in the hope that through discoveries or investigation some basis for the defence may be found.

When determining whether such circumstances exist, counsel must consider whether the defence would be consistent with the honour of the Crown. Reconciliation is generally inhibited by pleading these defences.

When considering pleading these defences, counsel must seek approval from the Assistant Deputy Attorney General. 

Limitations and laches

In cases where litigation is long delayed, equitable defences such as laches and acquiescence are preferable to limitation defences. However, these defences should also be pleaded only where there is a principled basis and evidence to support the defence and where the Assistant Deputy Attorney General’s approval has been obtained.

https://www.justice.gc.ca/eng/csj-sjc/ijr-dja/dclip-dlcpa/litigation-litiges.html