Gregor dumped the entire 10k (max at the time) into the rebellion. The game said that it was well spent, but that the large sum was noticed (hence the ban, but hey a record of it being done! I was fame chasing, it didn't give me fame sadly) The region didn't even budge, I asked some players there and they said they didn't notice one bit.
If the region is at 0 independence, it won't do much. But in a less stable region, it can easily push it over the edge.
We wouldn't want people to be so destructive with money alone, but tipping the balance is just the right thing. :-)
