A player in adventure mode can put out a lit candle by right-clicking on it. I expected that adventure players would not be able to alter the world similar to how they cannot toggle redstone dust (MC-184778) or dye signs (MC-138580).
You can ignite TNT in adventure mode
Adventure mode does not prevent dyeing signs
Redstone dust can be toggled between cross and dot in adventure mode
Cake can be eaten in adventure mode