Even *using* a company laptop in a public place poses a security risk, as people can look over you shoulder and see your data on screen. As for leaving it powered up with a stranger in a public place, that is stupidity deserving of disciplinary action. Our offices are classed as 'secure' in that access is controlled, yet we are still required to lock our screens when leaving our laptops in the office.
We are not allowed to leave laptops in view in locked cars, nor overnight/for any length of time (out of view) in locked cars at all. And these are all machines with whole-disk encryption.
Also, it is good practice, when refuelling your car to lock it whilst paying for the fuel. Many years ago, one of our employees failed to observe this basic precaution and had his company car, complete with laptop, stolen from the petrol station.
I am fortunate to work for a company which takes the security of its own data and that of its clients very seriously, and adopts technology and practices accordingly.