If it worked, the thin lines would either appear in both fields, or not at all. No, I don't understand that either, but it seems to work. Presenter 3 screens look surprisingly stable. Again, the results bear him out. Some credit, however, needs to go to both presentation graphics and TV technology.
Contemporary graphics use strong, large forms unlikely to be lost in a little smearing.
And the newest TVs include S-Video ports that modern converters not only support but depend on. S-Video separates the chrominance and luminance information, eliminating the interference inherent in Composite Video. Any converter will suffer if forced to use Composite Video or, shudder, an RF connection. The Presenter 3 Series uses directional buttons on the converter box to scroll hidden information back on the screen. Previous Presenters used software functions.