Part Time Cheaters

Recently I played a game in a tournament against somebody who was some 500 points below my rating. This player had lost all of their other games, and indeed had lost to me already in our first game.

Howeverin the second game it became clear to me that this person was indeed cheating, by getting assistence elsewhere. When I challenged them about this, they indeed got very angry, then promptly resigned, saying all kinds of terrible things.

After this I ran the game through 'Frtiz' and once all the books had been exhausted, their was only 1 move that was not first choice for 'Fritz'

So what makes somebody, decide to get computer assistence? here?