A form of Manglish (ColloquialMalaysian English), which is a short term word for "go-astern", or reverse. Normally expressed when you are driving a car.
Police on the Toronto (Canada) GO Transit system used to issue citations to riders who forget to cancel their prepaid ticket.
I could see the GOstapo in the next train car and suddenly realized I had passed the ticket cancelling machine and forgotten to punch my ticket for this ride.