think yourself lucky, flights from ORD to CPH or ARN are usually overbooked in my experience and volunteers are required to stop over and take the BMi flight via BHX the next morning.

ive found that if you hold a Y+ ticket and have your SA Gold card, you normally get priority for upgrading. Although the new policy of scrapping the upgrade vouchers hasnt helped so you get every man and his dog battling at the boarding gate desk - without stereotyping, its usually the americans who are flocking around it complaining about how they cant use their UA points.