Commands that write documents to a collection have been given the ability to bypass document validation:

• clone
• cloneCOllection
• copydb
• applyOps
• aggregate when used with $out (available for both command and method)
• findAndModify (available for both command and method)
• mapReduce (available for both command and method)
• insert - (available for only command)
• update - (available for only command)

I noticed that this flag is undocumented in copydb, but have not checked the other commands. Here's the jstest which tests these options