Locking the key in the car

Try it and see if it works before your trip.

Sports shops sell special waterproof pouches for such things.

If you want to leave the remote key in the car and lock it prior to leaving what I do is put my remote key way under drivers seat then after getting outside I close the door and lock the car from the outdoor key pad. That way the car stays locked and it can't be opened unless you have another key or use the external key pad to open.

For me the only thing that worked is putting the key in the car and manually locking each door by pushing down the locks.