I have to say, I really, really like expositionfairy's Tronzler!Theory and decided to take a closer look at all the times where Tron used his black Rinzler suits. Most of the time he kept the color scheme of his circuitry the innocent good-guy white except that time in "Tagged" right? When he turned orange without Beck seeing? (Not including the interrogation scene in Beck's Beginning obviously)
But there was also one more time when he did that... Even earlier than Tagged. Take a close look all the way back to "Identity", and you can see the the Tronzler orange colors of his suit.
It's this moment. ((Sorry I don't have a good screenshot but you can see the orange circuitry in this gif too))
And guys, one more thing... he snapped out of this Tronzler mode after he heard that Beck was most likely in trouble (possibly injured). He stopped Rinzler-ing after he noticed a close friend in peril. And what did Rinzler do in Legacy?? That's right, he saw Flynn and refused to harm him. He snapped out of the Rinzler mode because he saw his close friend. Tron later revealed that he thinks of Beck as a friend in "Identity". And why doesn't Tronzler want to reveal his orange self to Beck in "Tagged"? Probably because he was indeed tampered with by Clu and feels the need to be orange sometimes, without his friend knowing and ruining it.