Front emblem stolen (one with sensor)

You have a modern car. Modern cars have all sorts of sensors all over the place. This one has to "see" the outside for it to work. You can't hide that somewhere. It would be like removing your eyeballs and putting them inside your stomache. Sure you still have eyeballs but what use are they?

Thieves will steal anything. Your catalytic converter is a top prize as well. And no that can't go inside the vehicle...

If you have a car with the sensors, buy a real replacement emblem. Otherwise all sorts of wonky stuff happens. It has to be radio transparent. Unless I am thinking of a different sensor, the sensor is actually in the hood area and the emblem is expensive because it's like a pair of glasses for it. So in a way, they did hide the sensor the best they could.

Once you see the cost to replace, you might have the same idea the thief had...

 

Your image didn't display and you haven't answered if the sensor itself was actually stolen along with the emblem.

You can buy an emblem online (eBay) super cheap. BUT they will not be radar transparent and your car will slam the brakes on randomly (it will think there is something immediately infront of the car and you aren't slowing down!).

If the sensor is still there, then all the safety stuff should work kindof, it won't be calibrated properly, but better than nothing.

If the emblem is missing and sensor is there, don't cover it until you buy the real thing.
If the emblem is missing and the sensor is missing, then buy a cheap ebay emblem until you replace it

My "emblem" on the Leaf has radar behind it as well as a front facing camera and is on the charge port with lights on the inside section and very expensive connectors behind it. It's well over $2.5k to replace...

 

If you have the sensor and you put a cheap crappy emblem on, the system will automatically brake at random, HARD. This is an extremely bad idea. It's better to have no emblem than do it wrong.

 

I'm pretty sure that sensor behind the emblem has nothing to do with lane departure. That's a camera in the windshield since radar can't see paint stripes very well. But, as @2k1Toaster said a couple times, it could make your car do a panic stop if you block it. The sensor is directly behind the emblem, so if it's still there, you'll see it just by looking in the hole. You can also look down through the hood latch opening and see it.

 

The Radar is behind a sticker emblem isnt it? I have the physical emblem without radar, but im pretty sure the radar is a much bigger unit behind the glossy emblem sticker thing...? Kinda doubt its possible take of that unit without taking the front bumper off?