---- Canonical Question - About multiple querystring with similar content
TheOptimizationIdiot - 12:07 pm on Mar 6, 2013 (gmt 0)
There's a big difference between ignoring a parameter, and ignoring pages whose URL contains the parameter.
You're not ignoring the pages, you're noindexing duplicates if for some reason Google decides to spider a page with a parameter you've told them to ignore. Links still count. PageRank still get accumulated and passed. All you're doing is safeguarding against duplicate pages being indexed caused by a parameter you've said to ignore not being ignored for some reason.
There's no way it can have the opposite effect if it's implemented correctly, because the pages should not ever be accessed, and if they are then you're simply noindexing duplicates of the canonical version.
As far as your issue goes, why not just fix all the query strings with a couple lines of mod_rewrite and not worry about where they came from?