I suspect the regulatory environment in aviation is the strictest any developer faces.

As long as they don’t see who is printing out their emails, still possible to CYA - but it does draw a giant target on ones back if you’re obvious about it.

In a broad sense, not specifically related to not retaining data as a legal protection, institutional memory is somewhat overrated because of how much low-value content is retained and how it was a snapshot of how a different world was understood.