Yes, I've flagged a few hubs. If I come across a hub while hub hopping that obviously violates HubPages rules and standards (foreign language,copied articles, spun, too short, etc.), I do flag it for review. It is then up to the moderators to decide if the hub should remain published. I believe that requesting review of substandard articles helps to maintain a higher overall quality of articles on HubPages.
I don't usually check back to see what happened as the final decision is out of my hands. I've never flagged a comment or question.