What happens when every car uses lidar, or some other range finding technology? Won't they interfere with each other and cause problems?

I did similar in 1990. We had a Novell network and I simulated the text based login screen in a programming language called unicomal, and left dozens of terminals with it running logged into my user account. The network admin was convinced to log in under the pretext that I'd lost my password, and hey presto, one admin password grabbed, written to my user directory and an appropriate 'wrong password' message printed before logging out of my user account, leaving the admin thinking he'd simply typed it incorrectly. Ha! Those were the days.

I wrote a simple comic ording program for a friend's comic shop, and thought it would be a wheeze to occasionally flash up "Kill them" and "Kill them all" in the main window's title bar (an original idea stolen directly from 'The X Files'). Unfortunately, it had to be removed after a couple of months, due to one staff member getting increasingly irritable after using the software!! Though, on my birthday it still flashes up "It's Chris's Birthday! Go buy him a drink"!
More recently, I've added a randomly appearing link in the my work website's copyright notice footer. It takes you to a link of silly staff pictures, plus video of another staff member hurting himself on a snowboard, and more video of a customer singing songs to us! Craaaazzy. www.compman.co.uk/easteregg/