I agree with everyone else. While it may work once in awhile, it's just poor practice.

Its one thing to negotiate price in advance, or try to get upgrades if you are dealing with reservations or the sales team. But to just all out offer a large tip/bribe at the front desk is wrong. You are asking someone to who doesn't have the authority to do so to risk their job.

Can they do it? Yes, but the average, non-manager front desk person isn't supposed to be. If this became widespread in the luxury hotel world, there would be alot of front desk staff losing their jobs.