I’d say the opposite:

Any stealth game with a forced overt section should have a warning.

Examples:
Deus Ex: Human Revolution - Optional stealth game, but the boss battles just drop you in a room with the boss fully aware of you and that’s the fight.

Assassin’s Creed: Odyssey - Optional stealth, except for the battles for power where you can flip control of an area. No stealth allowed.