To get noticed, you have to have upvotes. If you have upvotes, that means that users appreciated the content. If, say, a company or person is promoting themselves and the community upvotes it, I don't see any problem with it. That's how it's supposed to work.
But I don't think that's what you mean by 'disguise'. I would guess rather that you mean that some entity is paying the reddit the company to create artificial upvotes (i.e. not originating from users) and maybe even paid commenters. I personally would be surprised if there were a lot of this clearly happening (there's a number of people on reddit that make a 'career' out of debunking stories, identifying brigades, etc).
Can you point to some popular posts presently on reddit that are examples of it?