In North America, General Admission = Reflection Section. I am 99 percent sure you will not have to buy a VIP package to buy RS tickets. It will be hard to get one though. There's only room for 225 people, and some of that space will be reserved for VIP.
Anyone know how many the CDT GA section fit?
If you're in UK, it's different. GA =/= Reflection Section. In the UK, the entire floor of the arena is standing, and therefore RS is a special section of GA.
The interesting thing is there is a price difference between RS and Regular GA in the UK (I think), but in the US, RS/GA is the same price as everything else in the lower half of the arena.