Haven't had chance to go through the code yet, but please make sure that players can not abuse this feature in a very unimmersive way (as they often do with Wardog's Vehicle3pp mod), by disabling 3pp camera view IF car trunk or hood is open.

This leads to silly looking cars driving recklessly around the map and players inside are unable to be shot at as they are supposed to.

Open hood/trunk to increase cover

Enter vehicle, click V and start driving (not)being blinded by the obvious obstacles

Example code below (Working on 1.29 with Wardog's mod):

modded class CarScript
{
	bool TRQ_HasOpenHoodOrTrunk()
	{
		GameInventory inventory = GetInventory();
		int attachmentCount = inventory.AttachmentCount();
		bool blocked = false;

		for (int i = 0; i < attachmentCount; i++)
		{
			EntityAI attachment = inventory.GetAttachmentFromIndex(i);
			if (!attachment)
				continue;

			InventoryLocation location = new InventoryLocation();
			if (!attachment.GetInventory().GetCurrentInventoryLocation(location))
				continue;

			string slotName = InventorySlots.GetSlotName(location.GetSlot());
			string lowerSlotName = slotName;
			lowerSlotName.ToLower();
			if (!lowerSlotName.Contains("hood") && !lowerSlotName.Contains("trunk"))
				continue;

			int doorState = GetCarDoorsState(slotName);
			if (doorState == CarDoorState.DOORS_OPEN)
				blocked = true;
		}

		return blocked;
	}
}

modded class DayZPlayerImplement
{
	override int CameraHandler(int pCameraMode)
	{
		HumanCommandVehicle vehicleCommand = GetCommand_Vehicle();
		if (vehicleCommand)
		{
			CarScript car;
			if (Class.CastTo(car, vehicleCommand.GetTransport()))
			{
				bool blocked = car.TRQ_HasOpenHoodOrTrunk();
				if (!blocked)
					return super.CameraHandler(pCameraMode);

				m_Camera3rdPerson = false;
				ChangeVehicleView(false);
				return DayZPlayerCameras.DAYZCAMERA_1ST_VEHICLE;
			}
		}

		return super.CameraHandler(pCameraMode);
	}

	override void HandleView()
	{
		super.HandleView();

		HumanInputController hic = GetInputController();
		HumanCommandVehicle vehicleCommand = GetCommand_Vehicle();
		if (!hic.CameraViewChanged() || !vehicleCommand)
			return;

		CarScript car;
		if (Class.CastTo(car, vehicleCommand.GetTransport()))
		{
			bool blocked = car.TRQ_HasOpenHoodOrTrunk();
			if (!blocked)
				return;

			m_Camera3rdPerson = false;
			ChangeVehicleView(false);
		}
	}
}