so giving "everyone" access to the System Volume Information folder means that I'm the only one who will access it.
Wrong. "Everyone" means any type of user, even "guest". Instead of "Everyone", you could call it "Anyone, no matter what".
System Information Volume folders are very restricted. Only the real "Administrator" account (not the group) and above can even *read* it. Lower level users that those don't even have reading permissions. So giving "full" permissions to "Everyone" is not something I would recommend (maybe some techguy would; it's up to you to follow it or not).
Here is my point: you think you "solved" something (that was not originally really a problem) by lowering your security barriers.
Is like saying: "I don't like that have to turn the knob to open my front door, so I'll just leave it open 24/7".