I guess they are free to post here and I guess people would be free to vote on them. Do not mistake votes with voting power, if some celeb buys steempower at this moment, I would be very surprised and I guess I would indeed applaud him for being so connected to reality. If it really gets crowded with them we would also be free to use a plugin or another client that blocks all celebs for example. If it would really be a problem to the steem-economy then I have full confidence that the community and the devs will solve this together in a creative way.