Aliysa Taking down a site when the limit is exceeded isn't yet roadmapped.
IMHO we first need to see the graphing and logging of this exposed (I understand from TICKET01168 this is coming very soon) so we can ensure it is accurate.
I then need a method to monitor people approaching the resource limit (not really just bandwidth, can be storage) and notify them.
I then need a method to notify me if people exceed the resource limit so I can more ideally move them to a larger more expensive package, or charge them an incremental overage cost; or less ideally suspend their access to more of that resource.
So really for me it is about i) having resource use monitored for volume ii) having resource use exposed to customer so they can self regulated before iii) having notification system for approaching or exceeding those resources and iv) having automation for actions when exceeding those resources.