There's also a design flaw with front disc brakes, in that the caliper should be ahead of the fork not behind. With the caliper behind, when the brakes are applied the wheel/axle is pushed downwards, trying to eject itself from the dropouts, particularly on the rotor side, which can (in my case) make the wheel tilt to the left. The lawyer lips on the dropouts and good quality skewers done up very tight are meant to help, as are using bolts rather than QR. Presumably the heavier you are the more momentum and grip and hence force you can put things on under braking too and probably worse on the road than trail, and maybe why a lot of the accounts seem to be from bigger riders. I ended up reading loads about it online as it worried me a bit, this page is pretty informative
http://www.ne.jp/asahi/julesandjames/home/disk_and_quick_release/ If it is just the QR, i was told to do it up as tight as you can with your hands and check it from time to time. IIRC the same physics/forces can cause a similar effect if there is flex in the hub/spokes too.