Another anecdote: Local friend works for Google in Asia. She is basically forced to relocate to SF for 1-3 years and work at a rather low salary (for SF standards) there on something unrelated to her current job.

I would suspect that part of the reason for such a "program" is to save on wages, which would be much higher for locally-hired staff. Her field is admin/marketing. Should be easy enough to find local talent for that. At a higher price.

I'm sure there are upsides to this exchange program, but having no real choice (except quitting) and working at a lower salary don't leave the best impression.