With the strobe set to the proper frequency, the sampling effect goes away. In the above videos, you're seeing strange effects because the strobe frequency is not keeping up with the cam rpm. As the cam rpm passes an "order" or multiple of the strobe frequency, you see things going backwards, then slow to a stop, then move forward. In that BMW video, it looks like the strobe just hit a maximum frequency and couldn't move higher to keep up with the cams.
On all of my videos I timed the strobe carefully with the cam rpm and filmed at steady-state speed. This eliminated strange sampling effects. As long as the motion is well repeated, you'll get a true view when you do this.