MacKay was clearly incensed at the time of the decision, which was made after 33 minutes. McGinn nipped the ball past the defender, who promptly stuck his foot out and the St. Mirren midfielder went down.
After the game, MacKay called McGinn a cheat, an accusation the Scotland under-21 international has denied. The SFA seem to agree with him as they won't be dishing out any penalty, but they may punish MacKay for his remarks.
At the time I thought it was a stonewall penalty, I'm not so sure now but it certainly wasn't a dive. Of course, it suits the SFA just fine to back McGinn on this one as it allows them to ignore the possibility one of their officials made another shocking decision.
Story source: The Paisley Daily Express