Should be only used when clandestine things are a major thing instead of some minor thing to do on the side of everything (e.g. optional clandestine activities instead of the main objective being that).

Although criminal activities do imply clandestine nature, they can still be done in open and criminal protagonist may not necessarily be involved in any criminal activities in the actual game story.

This is also common for military or such operations that are sensitive in nature or break international laws.

Stealth games should not be included just because they're stealth games.