Re: I can see both sides of the argument...
"Quite often thought needs to be given the to the "old way" of doing something, and compare it with a contemporary problem to try and justify what is right and what is wrong with, in this case Tim Cook's stance" -- Ken Moorhouse
A perfectly sensible approach ... but ...
"Let's say someone lodges an incriminating document in the vaults of a Swiss Bank. Would the bank accede to compelling legal requests to release the document?"
Ah, now that's the problem. If you are going to use analogies to form conclusions to the original case, they have to be analogous in the relevant respects. Try this.
A Swiss Bank vault may contain a document of as yet unknown value. There are four ways to open the vault
a) the emergency code, which is well known but will destroy any such document
b) the secret code to the vault, the knowledge of which has disappeared with its deceased owner
c) cracking the door lock somehow
d) drilling through the concrete into the bunker.
Now, the FBI, aided by the DoJ, want to do (c) but they want the vault manufacturer to make a tool which will open this vault. However the vault manufacturer demurs on the grounds that such a tool will open many of the vaults they have already sold.
If there's a good chance the document contains the date, time and location of a nuclear attack, then why not just drill (i.e. attempt to use electron microscopy to read the required info that the chips won't divulge). It's expensive but it might be worth it.
In this case, it's pretty unlikely there is such a document. Vaults known to have been used by the deceased that probably did contain such documents have been destroyed by him. He shared this vault with someone else (his employer) so he probably didn't put any incriminating documents in it.
So it's probably not worth doing (d). And if it's not worth doing (d) I'm not sure it's worth doing (c). However, because the US govt doesn't care about any of the other vaults, bizarrely including the ones belonging to citizen that it is its duty to protect,it is going to insist on (c).
It seems to me that the only thing the vault manufacturer can do is comply with the order but I think they have a reasonable case that the cost of this isn't just the tool, but the necessity of offering free replacement vaults which are invulnerable to that tool to all its existing customers.