Just thought I would add my 10p worth to this thread.
Bought my 06 250 new and have had no problems at all. No fuel leaking, no downhill starting problems noticed and no loose bolts from new.
Before the first shake down ride, checked everything and found nothing loose. Checked everything after the first ride and nothing loose.
After the second ride, took the necessary bits apart, cleaned and thread locked where needed. I would do this to any new bike and most handbooks would also recommend checking everything for tightness after the first ride as a new bike will need a bedding in period for tolerances to be taken up and stresses and strains put through the wheels, suspension, chassis and engine assembly.
I think the PDI on my particular bike must have been thorough (as all PDIs should be) and the carb well set up with good components fitted as standard from the factory.
The only gripe I have had is that the standard kill switch was sometimes sticking in the housing so I changed it for a Yamaha style one which is much better in design re prevention of dirt and water ingress.
So I hope this shows the other side of the (10p) coin. Had my bike been problematic it would have gone back to the dealer to give them a chance to rectify, after all the goods they sell should be fit for purpose and you have the usual statutory rights.
Just as an aside, I have a few tips for this model which have been gleaned from my own experiences of ownership and will post these shortly.