Any highly saturated primary color may show up blocky on miniDV. miniDV compression throws away a lot of color information, resulting in the blockiness. Some people will suggest that you lower saturation in-camera, but in reality there is nothing you can do about in-camera.
While you will notice the blockiness during editing, the truth is, the color blockiness won't show up on most TV's. If you are really concerned, you can look into Chroma Smoothing or Deartifacting filters (such as in the Magic Bullet suite). Do a search.
dont use a mac as it imports it as mov, and this, i truly believe, is the main issue with the color red and quicktime's codecs not being able to acpture this properly.
i say this because i recently purhcased my first mac, a macbook pro core 2 duo. This was my first time importing footage into final cut pro as .mov, and all of a sudden, the red horror that everyone had been talking about came upon me.
Never, through my years of editing have i had this problem when i import my footage into pc as avi, but all of a sudden, switching to mov, i had those blocky ugly reds.