The beauty of Coinkite hardware wallet is that you never have to connect it online. However, I am thinking: how can I be sure that the BIP39 seed they generate for me is actually randomly generated and not pre-programmed into the device?
Is it open source? If yes, you can verify this. If not, you can not verify this.
For example could Coinkite or Ledger could pre-program 1000's of seeds into the devices so that they know there is a high probability that I end up using one of these seeds?
Of course, this is trivial to do.
I just don't want having to trust a 3rd party, if it can't be guaranteed that these seeds are in fact generated randomly I will just have to generate my own private key using dice rolls via the Glacier Protocol.
I find it unlikely that anyone who has mentioned the Glacier Protocol in this context (on the forum; from what I've seen) has the sum of money that requires something like the Glacier Protocol. A simple air-gapped system which you wipe afterwards is fine.