The issue here wasn't that they were just using Amazon's API and then lost access. The Amazon TOS says don't store and display our old prices and, per the post, that's what PriceZombie was doing.
The lesson is that if you're doing something in violation of a partner's TOS and start to negatively effect their business, the partner is well within their rights to cut off access. Whether other businesses have or haven't been slapped down is only a secondary question.
The lesson is that if you're doing something in violation of a partner's TOS and start to negatively effect their business, the partner is well within their rights to cut off access. Whether other businesses have or haven't been slapped down is only a secondary question.