Fall through the cracks - Tradução em português

Pessoal, estou com uma dúvida muito grande em encontrar um equivalente em português ou entender o significado dessa expressão idiomática em português nos contextos abaixo.

Geralmente fall through the cracks é passar despercebido ou escapar de algo sem ser notado.
Mas não faz sentido nos exemplos abaixo. Conto com a ajuda de vocês na tradução.

I had a client who was too crazy to be in jail but too well to be in a psychiatric hospital. He fell through the cracks.

A friend, as a child, wanted to join a youth group that required the participation of both parents. He lived with his father, but his mother was dead. His request for membership was refused and he fell through the cracks. Twenty years later he was still bitter, and I understand perfectly.

An American student, who spoke Portuguese, applied for a student visit to Brazil offered by the Rotary International. The club sponsoring the trip was very pleased with the student's application, but he lived outside the club's zone and there was no such program in the area where the student lived. He was not sent to Brazil. He fell through the cracks.

I am thinking of moving houses, but I'm afraid to because I don't want to fall through the cracks.

Donal Trump on Oregon shooting: 'People are going to fall through the cracks'