I seem to recall that Singapore went after one or more pilots who were instructors in their abinitio program many years ago. The suit went al the way to a court in California and they prevailed. It was considered a watershed decision at the time.
This issue cuts both ways as a well known technology company in California lost several pilots who had just received ratings in newly acquired Gulfstream 650's and the Falcon 8X. Both of these ratings come at a very high price, this making the holder of such a very marketable pilot when looking for a new job.