I've never heard that before. Not saying its wrong I just haven't heard that. I did watch a video (Strain Hunters by Green House Seed Company I believe) where they quickly mentioned that some strains, particularly the fruity Sativa strains, can have red lines on them. Check out their India and African videos. It was one of those.
Even if it was true, I wouldn't rely on it unless you happen to know a particular strain really well. I would instead rely on the leaves, growth rate, and overall look of the plant to tell if it was stressed.