Hi,
In the last time we had several cases where spammers uploaded images on different wikipedias and used the pictures in html emails, trying to sell chairs, grammophones or whatever.
Usually the uploads were the only contributions of said user, and the license was missing.
It's maybe worth to consider disabling uploads on the projects which don't really need it but can use commons (such as the german wikipedia whose image upload policy is entirely compatible with commons and especially all the smaller wikis which are not constantly watched).
Crosspost to wikitech and wikipedia-l, but please answer on foundation-l since this is a project wide policy issue.
greetings, elian PS: I'll be away (on holiday) for the next three weeks, so don't expect an answer from me, only posting this to the list to make people aware of the issue.