Would be interesting to see however personally, i would hike the price of fuel right up for a select few and just murder all the other station employees in a buisness feud. Monopolising on the fact that people only want to travel to a few fuel stations due to distance. Would need to have a few...
personally i see this abused if its available to all.
My views, potentially allow it for civs if they can take fitness classes that you will unlock or you have a much higher chance of ragdolling someone when you hit them if you have spent excessive time working on your physical attributes...