In case you're wondering or have heard wrong, I checked with campaigsn that Clinton, Richardson, AND Obama are all returning Norman Hsu's donations.  The other interesting part of that story is all the donations he bundled from people who realistically wouldn't be able to afford the levels they were giving at.  Campaigns can't be expected to investigate every donor, though, and if and when more information comes out it seems clear that they are ready to do the right thing.

Of course, the mere fact that it is impossible for some people to contribute even a fraction of what others can seems more like an indictment of the system than of the donors.