While dumping a database with mongodump if a collection is dropped before it was dumped, the mongodump will fail.
mongodump should be able to tolerate such failures at least with --oplog option.
Steps to reproduce:
1) Create two collections with some records.
2) Start mongodump and when it starts dumping the first collecton, suspend the process (SIGSTOP)
3) Drop the second collection
4) Resume the mongodump process (SIGCONT)
It should fail as: