As Juan mentioned, it was pretty easy to dig up an example of a kickback allegation that occured within the pharmaceutical/medical/device industries.

Check out this example: http://www.nytimes.com/2013/04/28/opinion/sunday/another-alleged-drug-kickback-scheme.html

In this example, Novartis Pharmaceuticals enticed doctors to prescribe their medicine for off-label purposes by providing them with entertainment, gifts and appointments on advisory boards. This only occurred a few years ago. Its interesting to me that this occurs so often, considering how aware everyone (including the general public) is of this issue. This explains why at least at my company (a major pharma company), we are required to take online training programs every so often that explain these issues and advise us how to avoid them.