I'm going to generalize here, but it's not that far from reality.
Let's divide all Bitcoin users into two categories:
Computer knowledgeable: individuals who are either computer enthusiasts, professionals, or who are neither but have made a
real effort to educate themselves on basic computer security.
Not computer knowledgeable: not trying to be condescending, but everyone else...
Likewise, let's divide malware into two categories.
Simple Trojans: written by beginner programmers typically in a scripting or bytecode-compiled language, such as AutoIt, Java, .Net, etc., and does simple things such as scan for wallet.dat files in well-known locations and uploads them to FTP servers; is thwarted by wallet encryption with anything but simple passwords.
Advanced malware: written by professional black-hats and sold on the black market to individual who customize and deploy the malware; is capable of exploiting one or more OS or application vulnerabilities, attempts to hide from anti-malware products and security sandboxes, and will patiently search for a variety of information to steal (or encrypt for later extortion) from a variety of locations (including typed passwords, screenshots of on-screen keyboards, and who knows what else).
User Type | Likely to be infected by advanced malware? | Likely to encrypt their wallets? | Likely to follow your advice? | Likely to be infected by simple malware? |
Computer knowledgeable | Yes | Yes | Maybe, but they know it wouldn't do them much good. | No |
Not computer knowledgeable | Yes | Maybe | No, even though it would help them. | Yes |
In other words, I would argue that the type of user that this sort of security-through-obscurity would help (those who get infected by simple Trojans) is the same type who wouldn't know enough to implement this advice (or for that matter, to even encrypt their wallets in some cases which would help against simple Trojans).