In the movie Following, Cobb takes Bill to a house where the woman walks in on them. I was wondering if that was Cobb's plan or it was just out of luck. I thought it was planned but the fact that Bill found the key confused me. How would Cobb have known that Bill will find the key?
I believe he did. I don't have a solid reason why Cobb could count on Bill to find the keys. But there are a few clues that suggest it was planned.
Cobb wanted to scare Bill and make him change his look. The only way to do that would be to have a victim see him and recognize his face, but if that really happened they would be blown. And if it was a setup, Cobb would have had to have an excuse for why they were not blown, so he came up with a very deliberate that would be convincing without taking any risk.
Cobb also talks about making Bill change his look later in the movie.
Almost every bit of that burglary contributes to Cobb's plans.
Also later he says "3 spare keys in a row would raise suspicion" this is also somehow suggesting that the key was planted.
Also, if the woman was not in his team he would not insist that they stay in the restaurant because she would be the best witness for the police. She would be the only person who had seen them together and her testimony could back up Bill's story to the police.