They're not falling for anything, its just plain and simple greed. My father was in the radiology area and he constantly received 'bribes' (didn't accept them, but had the offers).
It's very clear in the industry that it goes on, and anyone that partakes is a scumbag, in full knowledge of what they're doing.
This in an industry that is meant to heal people, not be part of the problem we're facing with rampant corporatism and out of control greed.