Specifying exactly what would be disabled by disabling scripting would be a good documentation addition. It would also be useful to mention the "--noscripting" option somewhere in [1] and [2].

[1] http://www.mongodb.org/display/DOCS/Server-side+Code+Execution
[2] http://docs.mongodb.org/manual/faq/developers/#how-does-mongodb-address-sql-or-query-injection