I'm concerned primarily about the US, but also UK and Germany.
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The common way to ensure customers that you actually respect your own rules is to ask a third part to audit and certificate your business. If it is important for you, ISO provides a bunch of normative document that certification organization know. The best known is ISO 9001 for general Quality Management, and the IT counterpart is ISO 27001.
So my opinion is that the best proof you can provide to you customers is a ISO 9001 + ISO 27001 certification.