Sigh, ok lets do this quickly from the top, as we haven't even discovered a graviton and it's all speculation
Gravitons would be heralded as particles in a field which would be effected by energy and/or mass. So given energy is a "fictional" quantity technically you get the situation where a movement of energy or mass creates a runaway effect creating more gravitons. It is the situation that a country decided to leave it's printing presses on for it's money.
The post you have given simply says that is okay because the observer will see that the new created gravitons have the same combined currency. So in your money world if a country keeps printing presses on the currency devalues relative to some other country.
So I guess you could say if I devalued the USA dollar by 50%, my dollar is worth less but the entire GDP of USA is still the same when expressed in Euros but twice as much when expressed in USA dollars. That is the same as your post statement above.
So although correct it doesn't solve the problem because the gravitons would continue the process until there was infinite of them all worth nearly nothing. The same thing happens in economics and it is called hyperinflation, if you really leave the money press on.
So lets look at the proposed process, a graviton in a small space has something happen to make another graviton pop into existance near it. That energy in the space section causes yet another graviton to pop into existence. This cycle continues infinitely and we would say the graviton theory is nonrenormalizable.
The usual way to stop the runaway process is to invoke planck distance. That two gravitons can't exist in the same planck distance and string theory for example would give you a physical reason for why that is.
The alternative answer is the process is somehow held in check and as we haven't discovered a graviton that is a bit hard to even guess at what.
All pure speculation take whichever answer you like best.
