Reminded me of that time Greece declared bankruptcy. They shut down the banks to prevent people from withdrawing their cash. Senior citizens were out on the streets lining up the few working ATMs to get their pension. Government basically took their money hostage.
I don't doubt the Chinese government is capable of this. Even if the massive withdrawal won't ruin the economy, the might block the bank-run just out of spite.
I do not think they are hired by in the true sense of the word, but that they may have been deliberately misled to do what they do now. China wants more control on HK, and citizens have two options : to accept that they are part of China and adopt its laws, or to protest and thus provoke China into military action.
In any case, this is a win-win situation for China, they will get what they want one way or another.
I remember seeing claims from protesters that Beijing is "seeding" the protest with their own people to cause more violence. Beijing might not have started this but they'll definitely try to shape it into something that will benefit them.