aftermarket PAC on leased truck

My cousin is driving me crazy! She has a 2002 BMW X5 with the parking assist control and of course got spoiled parking her truck in the tight places in LA, which by the way did not prevent her from getting all kinds of dings on the doors… Anyhow, I was wondering if she can lease any other truck and have a Parking Assist Control installed as an aftermarket accessory and don’t mess up her lease. I remember from my previous leases it was some kind of a stipulation on my lease that did not allow any modifications on the vehicle. Thanks for your help!