A buy-up from someone already on board isn't the same as buying cheap baseball tickets. I was directly responding to the person who asserted that sports venues don't sell last minute tickets cheaply - they absolutely do.

The idea that selling a last minute upgrade somehow "cheapens" the product, or that not selling them "protects" the product is a little absurd. Some of the world's best premium class products sell last minute upgrade, with no effect on the perception of the product.

One way to differentiate such an offering is to remove certain soft products from the offering, such as the complimentary chauffeur service or lounge access. You can differentiate pricing into segments without "cheapening" your product. In the baseball example, the tickets are standing room only. If you want to guarantee a seat, you have to buy a ticket ahead of time.