Not yet, but it doesn't surprise me.

This situation is very interesting. In my own experience, where infringing material has been published on their servers (e.g. blogspot) they have been very prompt to remove it when they are alerted.

Here (as it in their results), it is obviously published on their servers, but at the same time has been generated by their algorithm from material published elsewhere. In my view this has important implications for their snippets, as anything published in a snippet could be infringing in the same way.

What have you done about it (or what do you intend to do)?

I have raised DMCA notices and Google dealt with the first fairly promptly and removed the offending material - the second was earlier today.

It just seemed to me that the snippets are raising sites to prominence that have been buried up to now, possibly for good reasons (i.e. duplicate content).