>>> from pymongo import Connection
>>> from bson.objectid import ObjectId
>>> c = Connection(safe=True)
>>> c.test.foo.insert({'_id':1})
1
>>> c.test.foo.insert({'_id':1}, safe=False)

Expected: no error, because 'safe' is False

Actual: DuplicateKeyError.

update() and insert() can be expected to override the collection's, database's, and connection's 'safe' setting same as for 'w' and other getLastError options, but don't for safe=False; only for safe=True.

Also, at least in Python 2.7.1,

Connection(wtimeout=1000, safe=False).safe

is False, but should be True. The final value of 'safe' when a Connection, Database, or Collection is given safe=False and getLastError options is unpredictable.