I saw a bit of the game last night. Towards the end, a Swindon attacker knocked the ball past the 'keeper and could easily have gone down. He didn't, but the angle was just too tight for him to score.
The commentator and pundit (not voices I recognised) then discussed whether he should have gone down and the commentator opined sagely that there is no right or wrong in that situation. He went on to say that going down would be professionalism but couldn't find a word to describe an attacker staying on his feet, presumably because he didn't want to say honesty and playing to the rules.
They concluded that although the incident didn't matter, it would have been crucial if the score had been 0-0 at the time. So, there we have it, flexible morality.