New Scientist recently undertook an informal study to see if red is off-putting in a testing environment. 

They set up two quizzes, each consisting of the same 15 anagrams. One quiz was predominantly red and the other blue.

On every attempt to access the article, a pop-up appeared requesting that you take part in the test. The colour of the text and border of this box was randomly selected to be either blue or red, corresponding to the colour of the text and border of the anagram test to which it linked. They then gathered data on the click-through rate for both colours, and the relative success rate.

They got roughly the same follow-through rate for both colours – 8478 for red and 8550 for blue – so the colour of the pop-up did not seem to have an effect on how attractive a prospect it was to take part in the quiz.

They also found that the readers scored an average of 63 per cent in the quiz, irrespective of whether the text and boarder colours were red or blue.

See http://www.newscientist.com/article/dn18071-colour-psychology-quiz-the-results.html