Paul,
I think I see where your coming from. For their privileges, market-makers (stocks, bonds, options) are obligated to display “guaranteed” prices for certain quantities. If you submit a buy or sell order, the price on the screen is what you’ll get assuming the price doesn’t change between submission and reception of order. You could use a “limit” order to avoid a worse price.
The majority (if not all) of futures market consist of speculators, you and me, willing buyers and sellers. There is no guarantee of price. No-one is obligated.
Grant.