Does red-line curve denotes better result in a graph? In a colloquium, an eminent senior professor showed a graph from a peer-reviewed journal (published by some other group). The graph contained three curves: 


black dots (blurred)  
black line (blurred)  
red line (thick and bright)


All these curves in the graph reports the same property (obtained with different methods). 

When talking about the graph, the speaker mentioned, "Since the authors thought that this data (by pointing the red line) is most important, they have used red line"

My question is, is there such practice of using red-line to highlight good results in research articles?  

Note: I ask this question because, in Origin Software, the first and second curve are, by default, black and red. If those colors are used, it may given an impression that the red line graph is the better result (compared to black line graph).
As far as I know, there is no well-established standard. The only universally recognized guideline is "use colors that are well visible, also when printed on black/white (if it's an article) or displayed on a beamer with bad colors (if it's slides)".

I think the most likely explanation is that the speaker was joking.

Personally, in my talks I like to use what I dubbed the "Star Wars light-saber color coding": the 'good guy' (new algorithm of which we are trying to show the merits) is in blue, the 'bad guy' (leading competing algorithm) is in red, and green and purple are used for additional variants (with green=good-ish and purple=bad-ish). But that is also a joke and not a standard.