We should also be granting Amazon the benefit of the doubt unless/until they do something objectionable. Neither of these expecting-the-worst scenarios -- that these employees are facing legal troubles from former employer, nor that their former employer is likely to give them legal troubles -- should be assumed without evidence.
That some other 'big company' once before did something similar isn't enough to suggest there's trouble lurking here. Maybe it's enough to ask the earnest question -- "do they have Amazon's blessing?" But not predict problems -- "can't see how Amazon will be happily quiet with this situation".