I have not seen anyone report that their car was restricted, or had any problems with Tesla servicing their car, after they had their battery pack repaired or replaced by a third party. (Which is totally different than how Tesla treats totaled/salvaged vehicles.)
Sure they do. They will sell, and install, a replacement battery pack.
As this discussion keeps bouncing between safety, warranty / quality, legality (tampering) and integrity concerns, I'm not sure that Tesla’s willingness to take your money (to have a new / replacement battery installed) would be in doubt.
Are Tesla any happier with salvage parts remaining ’in the fleet’ than salvage vehicles?
While safety is very important, so too is meeting claimed performance levels at a stated price. In a major sub-assembly like the battery (a misleading name imo since battery in my mind refers to a group of cells while our car hv batteries are far more complex than that) there are many potential points of failure that effectively render the whole 'energy module' (aka battery) useless to typical owners - as well as devaluing the car it is part of. Why should it be ok for Tesla to decide that an identifiable hardware issue within a complex sub-system can be remedied by changing the specifications / performance to mask the issue?
AFAIK there is no way for an owner to retain the (substantial) value of their own specific 'battery' in the event of an internal component / board fault while remaining assuredly within the Tesla approved system. You should not have to turn to the dark side or wait a couple of years plus several months recalibration to (arguably) get back what you paid for.
Imagine being obliged to write off an ice motor because it needs valve stem seals or replacement timing belt / tensioner or water pump. Would it be ok to tell the owner to increase their journey times or use thicker lubricants to mask the problem? Not that any one has done so, but talking about 'battery failure' or 'issues' makes it feel like the same discussion could be had about a conventional 12v battery as the traction energy pack / battery. You would not say that a 12v battery had failed just because the starter won't crank due to corroded battery terminals. It would be unacceptable for a manufacturer to weld the hood shut 'because it's dangerous in there' which would effectively make the battery terminal corrosion terminal for the car unless the owner breaks the warranty seal / weld! But imo there is an element of that with Tesla's approach to traction batteries.
Imo this all highlights gaping holes right at the heart of Tesla's offering. (previously mentioned need for battery core charge and regulations for tweaking software without clear rules / disclosure)
And I would accept that some batteries have been replaced under warranty, but is that part of a transparent, accountable process?