As I understand things, this is not precisely correct. The tier 1 ISPs pay per line speed at their overseas connections, not per gig or terabyte. Capping is a cost control mechanism to limit the contention on these lines, so that less line speed is required. The peering-type connections they have in the foreign country cost the same as anyone else connecting there. The only additional cost is the cost of getting the data there and back via SAT-3, SAFE or satellite. And this does not appear to be as high as they ( Telkom especially ) like to make us think it is from what people here have calculated, except maybe for satellite. If this is correct, low caps, or even caps at all, are just super-profit generators for a company like Telkom.
I might be wrong here about some of the stuff, but I don't think so.
I do think that we are conditioned by Telkom propaganda in a massive way though, and agree with Nick333 about the little old lady. We get excited when ICASA talks of raising the cap, but in reality caps are just rubbish. You can do your "user management" still, just buy more line speed so that the little old ladies can do their 700 Mb, and the leeches can do their 100Gb. You can still make good profit without raping everybody.
Any rational replies - I see the flames are heating up around here sadly.