When I arranged to take the bike in I asked if balancing was included and was told yes. I watched the fitting and they didn't do it so I asked and got the response as above. Fair enough, on a 'modern' bike they might not need to be balanced, but this would be the first set this '92 bike has ever had that haven't had weights attached to the rim.
When I took the bike elsewhere to have it rechecked, they found it needed a couple of grams on each wheel - was I being played for a sucker by these guys?
On a car, a little bit of eccentricity of centripetal force probably isn't going to affect handling significantly, but on a bike isn't it safer to try and line everything up to give yourself the best chance of aiming it well? A little snaking while braking or fishtailing while accelerating, might be exaggerated to a dangerous level by a little imbalance, wouldn't it?
I honestly don't know - I'm a layman, but this seems to make intuitive sense to me.