It's a bad thing compared to NOT starting it every fortnight.
As Doc says the engine wear occurs when an engine is cold, all the tolerances are tight, the oil isn't up to temp. If you start an engine and run it for 100m as you describe it will wear the internals as badly as if you went off for the day. The other issue is that the engine will produce quite a bit of water as it warms up, which is normally evaporated as you run at full temp, this way you can cause internal corrosion issues.
I don't play with bikes in winter, nor do I squirt oil down plug holes - I had to strip a Honda 4 one year after I did that to get it going again.
BUT.
It is YOUR bike. If you like to get your bike fix once a week pootling up and down the car park, and you are aware of the above, then go for it. As you say it is no worse than actually running it. It would be a concern if you had long term plans for the beast, as you would wear the engine disproportionally to its mileage.
At the end of the day it is your decision, the above is just so you can make the decision with all the facts. :cheers
