I believe you're asking if a business' competition can squash their competition's posts via downvotes if they have a large stake. I don't think a business' focus will be on posting blog entries if they're running a business on the chain. I think the chain would be integrated into their business, versus using an application to promote as a high priority. If that is for some reason the case, I don't know what the solution would be. It'd look pretty tacky of the larger SP-holding competitor to do that, so it could be a bad look for public relations.