Secure deletion
I fear the Mahatma's profession may have induced a suspicious default state of mind. For many years, both personally and professionally, I've used a readily available simple utility to periodically securely delete cached data.
I have a couple of reasons, neither of which implies mischief. One, cached data is a great way to introduce malware which can evade AV applications at boot-time - or at least before the OS and utilities are fully up and running - and secondly to free up space, particularly where it's limited by the currently quite small SSDs in general use.
I've also installed this on many other people's PCs where I know their understanding of security issues are very limited and taught them to run it before shutting down. No point in leaving, for example, cached email addresses, passwords etc lurking about. PCs get stolen too. Obviously this procedure isn't bullet-proof however the use of these utilities is, in my experience, far from being automatic evidence of illegal behaviour.