Well, considering most HDTV sets upscale 240p/480i to 540p, there would be pixilation, you just may not notice the "doubled scanline" appearance.
THAT'S where the small lag comes from, de-interlacing for the upscaling.. No CRT HDTV today can do 240p/480i natively, due to price for parts. So they are instead 540p/1080i...