From the GlobalPass website:
"GlobalPass mileage does not expire as customers remain active. All earned mileage will expire if the account does not reflect a qualifying activity within 36 months from the last Service Date.
Qualifying activity is defined as earned mileage credits on a GlobalPass participating Service Provider or transferring miles INBOUND from a Participating "Transfer" Program.
Transfer of miles OUTBOUND to a Transfer Program is not considered a qualifying activity."
Of course, I guess someone who was really desparate could transfer points back into GlobalPass from Marriott or HHonors or somewhere to keep their account active too.
Djlawman