Dumb Question, we store all the bitcoins sent to cold storage in a vault that is a faraday cage shielded to protect against something like this.
Well, it might not be that big of a deal, but if it's what you're doing, I wouldn't think it would *hurt* to advertise that fact. There would definitely be people who choose your service over others just for that.
On a single piece of media that could spontaneously fail for any reason?
I would be more comfortable hearing that the private keys were kept in two places and were maintained in such a way that, for example, an unexpected death of the custodian of those coins wouldn't result in their loss, while meanwhile ensuring that they're adequately protected from theft.