Last modified: 2014-02-26 12:55:21 UTC
I logged a Schema:Campaigns event with a bad campaign parameter not listed in https://meta.wikimedia.org/wiki/Schema:Campaigns and it logged as "clientValidated":true. Looking at extensions/EventLogging/includes/JsonSchema.php it doesn't look as if there's code for this.
Related URL: https://gerrit.wikimedia.org/r/70062 (Gerrit Change I700ec58de1be6de01093cc57b5ec6f4b23429f3d)
[moving from MediaWiki extensions to Analytics product - see bug 61946]