You can't ever accuse a newbie of cheating. Most of their play makes no sense anyway so they can occasionally luck into nutted scores, and good luck pinpointing a "fishy" play that you can put down to tmi and not just cluelessness.
Also, I won my first ever DC.
http://www.triplechain.net/challenges/6344
You could think that, for example, my blocking off 6s in Round 6 shows that I knew there were no more in Rounds 7-8, but no, I was just terrible.
Although I apparently discovered (luckboxed into) the advanced chain setup (with 5s) pretty early on.