If they are trained to drive or 'operate' different cars then
i'm fine with it.
There was once, one of my friend drove us home in our other frien's
car as he is the only sober one.
When we stopped at the roadblock and down came the window, we just
smelt this very thick burnt smell. I thought it was the haze and
the officer didnt say a thing, so off we go.
No doubt, the temporary driver felt that the car was heavy and
reluctant to accelerate, even failed to overtake a lorry! The owner
of the car even said that his car is just sluggish in
acceleration!
When we reached our destination, i opened my door and saw plenty of
smoke coming out of the right rear wheel. I immediately poured a
bottle of mineral water over the brakes to cool it.
The darn driver didnt release the foot pedal of the handbrake fully
as he wasnt familiar with it.
Bloody hell! all drunk! 
