the "date_browser" view from the date module does this & the logic for why is valid. Need to detect arguments even if path doesn't define the "%".
Patch takes care of this situation. If you do not have validation of the argument, then you could still get a 200 on bad input; if this is the case, odds are error is due to improperly configured views.
related issue #798602: Views: Implement Date Argument Validation
Automatically closed -- issue fixed for 2 weeks with no activity.
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