Monetary penalties are different from trust erosion in that they are the test of whether trust can be restored, ie you are acting very unpredictable => I am going to show you I'm paying attention and hit you with a penalty and watch your response. If you continue to show you are unpredictable => I plan an exit so that I don't _have_ to trust you, ie trust erosion.

Ultimately if there's too much unpredictable behavior the pain endured will become higher than the pain of eroding trust... which if trust was truly eroding would be signaled by establishment of monetary systems independent of the US, probably with the International Monetary Fund as a base, backed by at least India, China & Europe.