That seems hard to believe. It is very nearly impossible to hold the bicycle for more than a few seconds when it is standing still, but I can ride it for half an hour (traffic permitting) with no problem.
EDIT: Here's the link: http://www2.eng.cam.ac.uk/~hemh/gyrobike.htm
The enhanced gyroscopic stability appears to be a near constant-rotating balanced mass; it's still rotating with the wheel but at an angular velocity such that the gyro effect is constant (ie reducing slightly as the wheel's own weight adds to the gyro effect?). Thus you get the gyro stability that you get when riding quickly with no hands but constantly, even when riding slowly.
It's neat for sure and bound to do well as it's hiding the stabiliser away and pretending the kid is more advanced, hence parents will love it as their kids will look "better" than the neighbours kid!