Tesla's stance on salvage vehicles definitely needs work, no doubt about it.
As for superchargers being "free for life," unfortunately regardless of what Elon Musk has said, this particular line item is not in any of my paperwork after three Model S purchases. No where in any of my documentation, purchase agreements, order confirmations, etc does it say anything about superchargers being free for life and/or accessible forever or anything else along those lines. The purchase agreement specifically excludes any verbal promises, if I recall correctly, also. There is also no mention of 3G, free or otherwise, in any of the legal paperwork. Do I believe they'll go back on that particular feature? Probably not, would be horrible PR. Do I believe they're eventually going to start charging for 3G? Yep.
The only thing about supercharging in the documentation is an item that says "Supercharging" and a line that says "Supercharging enabled." This, to me, just means that the hardware in the car is unlocked and able to do DC charging.
As for 3G, it makes perfect sense for Tesla to cut off 3G access to a car that has been reported as a total loss. Why keep paying for service for a car that is in a junk yard?
Supercharger network access probably just disappears along with it. As I said before, I wouldn't want someone with a crappily repaired S breaking superchargers.
It is pretty much implied with any salvage situation that you're kind of on your own. The car was deemed a total loss for a reason.
I do believe Tesla needs to open up service documentation and diagnostic tools to 3rd parties, but I don't believe that they should indefinitely provide ongoing support for things like 3G and supercharging for vehicles not serviced and inspected by them on a regular basis.
Honestly, I think the $1200 inspection is more than reasonable, especially if it allows access to the supercharger network after passing. Even if it were a $1200 yearly inspection, that'd still be reasonable, IMO, to permit a salvage vehicle access to the infrastructure.