They have other fare classes available. Back in July, I travelled with an acquaintance who bought a non-mileage earning fare SIN-EWR-SIN (I don't remember what booking class it was specifically, but it was definitely non-mileage accruing). The <<expletive deleted>> paid ~S$2000 for this ticket, when a mileage accruing ticket cost $2100. This was when the double miles promo was going on and he could net about 38,000 miles by paying S$100 more. I felt like kicking him