Way back when, we had usenet, telnet and gopher, and local BBS's would sometimes have a private stash of cough shareware.
Prior to usenet etc being easily accessible to people outside of educational institutions (the majority of the 80s), it was more common to share programs via "sneakernet" on floppy disk as well, these would often contain a text document that would say what other programs were available and some clues on how to obtain them, but usually it was just a viral spread among friends and acquaintances.
Cracked software would often include intro screens and trainers, the intros sometimes included animations and catchy music to showcase the elite skills of the cracking crew and build reputation, and often they improved the software so it would load more quickly, unlock hidden functionality, or give you infinite lives etc. This spawned the DemoScene, which still exists today unrelated to piracy but historically rooted in the 80s cracking scene.
Here's a compilation of crack intros from 86 to 89 - https://www.youtube.com/watch?v=SFqBkSJOYOQ (skip to 11:40 and you'll see an advert for "cleveland cracking service" with a phone number for an example of how stuff got around before internet was common)
Essentially even back in the 80s and 90s there were the serious crews trying to demonstrate their awesomeness and generate rep, and dumb kids like me naively sharing "free stuff" we were given on disks because we had no idea what things like copyright and licensing even were, let alone stopping to consider whether the stuff we were loading onto our machines had any malicious intentions.
So I'd say that the idea of building reputation and trust in regards to piracy "crews" has a long history going back even further than 20 years, well before the web was common in homes, and I'm at least aware of early to mid 80s cracktro / intro scene materials so perhaps ~35-40 years is a good guess?
Who are your clients? Are you aware that everything that's uploaded to VT becomes public? As in full file contents, not just metadata & scan results. There's no harm in uploading .exe's there, but you should at least warn them not to upload private documents.
Also, VT results are trash for anything new so "all green" doesn't necessarily mean you're safe to run stuff if it also happens to be the first time VT has seen the file. It's not even the VT's fault, AV's suck and everybody knows it. The value of VT is that once something gets detected people can go back in time and look for other incidents that had flown under the radar previously.
Not running pirate software is the only valid path for security.
I don't remember when PirateBay or other Warez sites first appeared, but they have been around for at least 20 years. I remember people were even using Blogspot to promote their wares/z with links to RG, FS, DF, etc.
I know and trust(?) the results of Virustotal, and I tell all my clients that when in doubt, drop that bad (?) boy in VT and let it scan it.