Continuity mistake: As the boys are running through the sewer tunnel, both of them fall several times, and they are covered with dirt and sewage. When they come out and face the bullies, their clothes are clean.
Continuity mistake: When the family moves into the new house, the father rips the former owners' name sign off the front of the house. A few shots later, it's back.
Continuity mistake: At the end when Mike receives the first postcard from Bobby, the flag on the mailbox is up, meaning there is mail to be picked up by the postman. Then when he takes the mail out and runs towards the house, the flag is down without him touching it.
Continuity mistake: In the first scene with Bobby's first postcard, he writes his name as "doddy" as a young child might, reversing the Bs. Later, when you see the postcard hanging by a string, it is written "bobby" instead. (01:44:55)
Answer: He was in a very small part of the movie and at the time he had already become quite a famous star. If his name were attatched to it without being uncredited, he would have had top billing. He probably decided to remove his name from the movie so the younger actors could receive more attention. The same type of thing happens in quite a few movies I can think of.
jennibee