They can, however it really isn't as smooth an experience for the user and Microsoft knows this well.
One only has to look at how it works for Xbox Live Arcade games for an idea on how seamless this is. Give the user enough so that just as they are hooked, the trail runs out. One click of a button is the entire upgrade process. No dumping out to a different application (Marketplace) in order to purchase the full game, just a one second click of a button.
One only has to look at how it works for Xbox Live Arcade games for an idea on how seamless this is. Give the user enough so that just as they are hooked, the trail runs out. One click of a button is the entire upgrade process. No dumping out to a different application (Marketplace) in order to purchase the full game, just a one second click of a button.