Originally Posted by http://faq.ua2go.com/display/4/kb/article.aspx?aid=9573

Are there different oversized, overweight and excess baggage allowances for certain travelers?
Yes, Global ServicesSM customers, Mileage Plus® members with 1K® or Premier Executive® status, and customers with Star Alliance® Gold status are exempt from paying excess baggage fees for their third bag and are allowed to check baggage up to 70 pounds (32 kg) without paying overweight baggage fees. Companions traveling under the same confirmation number as these customers (up to eight companions per reservation) are exempt from the same fees.

In addition, U.S. military personnel (and/or dependents) who are either active or traveling on leave in conjunction with a permanent change of station (military ID required) are exempt from the fourth bag fee, may check baggage up to 115 linear inches (292 linear centimeters) without paying oversized baggage fees, and are allowed to check baggage up to 70 pounds (32 kg) without paying overweight baggage fees.