security perspective - leave enough room so you can quickly maneuver car away from potential carjackers, thieves, kidnappers, assassins, crazed lunatics, government agents....
To be fair, today's cars offer little to no vantage to the driver over the edges of the vehicle; drivers literally cannot see where the edges of their vehicles are and it makes it difficult to maneuver in close proximity other cars and stationary objects. Drivers have to guess and most choose to err on the side of caution when making piloting their cars in tight quarters. I was able to deftly guide an '86 Chevy pickup truck through tighter spaces than my 2007 Camry despite the marked wheelbase and size differences simply because I could see every edge of the Chevy and zero edges of the Camry. It's crap! And incredibly frustrating.