There's still no evidence that Amazon has ever done this. AFAIK potential customers are more concerned that AWS will use utilization metadata as a proxy for their customers' financials, like Facebook was using Onavo traffic data to decide which startups to buy and which to clone.
The worry is not that your provider will hack you, the worry is that your provider will silently steal your trade secrets.
Cryptographic keys that control identity and money are good distilled examples of this.