Originally Posted by RSSRNotInIndia

There is a science to this ; ).

Paid gate (and easy/united.com) upgrades are offered only to those passengers who have purchased certain fare classes. Further, a specific dollar amount is assigned based on flight length (3000-4000, 4000-5000 miles, etc.) I don't work at the airport, but I have access to the profile, maybe one day I'll post the contents here. : )