Criminal hacking charges for the people involved in pushing the change and full liability for all cost in cleaning it up. This means people will be really careful and take steps to not make this mistake again.
It is an interesting thought - opening yourself to charges of criminal negligence for misconfiguring devices/software would be a big change for our industry.
All they did was announcing a better route for those prefixes and other routers obliged. I'm sure swamping their own network with unwanted traffic was punishment enough.