How much of Reddit's engagement is faked is up for debate - I suspect it's less than we think. However, it'd be really funny if, say, when Reddit IPOs, someone at /r/WSB catches onto this and triggers a bunch of people shorting the stock.
[0] https://www.youtube.com/watch?v=zmeDzx4SUME via https://www.themarysue.com/reddit-fake-account-origins/
[1] https://www.reddit.com/r/SubredditDrama/comments/13p889x/red...
And if it wasn't, everybody would be doing it. What makes you think reddit would have an advantage in doing that over anyone else?
Some malicious actor is fabricating 100 comments a day about the nitty gritty of the New York Times crossword?
But Reddit probably has the scale to do without in popular parts of the site.