Quebec's legislation contains a provision on those types of situations, specifically. It authorizes the commission to cease to examine a matter if the application is considered to be vexatious or frivolous, or made in bad faith.
The act contains another provision to address what you mentioned. When a public body, which has just 20 days to respond, receives an access request for several thousand documents, it can ask the commission for permission to disregard the request. Those mechanisms help keep the system in balance and address the issues you referred to. In Quebec, we don't do that through fees but, rather, through specific provisions of the act.