What you say is tempting, Federico, I could probably retire if I get, not 500€, but 2€, from everyone using my works on Commons without any effort to try to fulfil the license (some do try that but do it anyhow wrong, e.g. stating Wikipedia instead of the author + CC License). Is that the way I should go? We had some cases in the past about this and you know, if people find out that via Wikimedia you can get rich, it could get funny.
Stressing the compliance with the licenses or providing easy ways (like the license generator [1]) can surely help but I was hoping more support from the Foundation or CC, that never came.
WMES is starting a "service" for photographers having this kind of problem (channeling complaints, creating a web page with information about dos and don'ts, setingup an email like
legalissues@wikimedia.es). Maybe it makes sense to foster some exchange among the chapters about this topic, which is, believe me, very frustrating for people like me.