> what's stopping people from just stealing sub-blocks from ISPs? The thief has to either be upstream of your connection, or peered at an extremely high level

> what's stopping people from just stealing sub-blocks from ISPs? The thief has to either be upstream of your connection, or peered at an extremely high level with others trusting their BGP advertisements. There was a hilarious incident not that long ago where the Pakistanis accidentally blackholed YouTube's IP-block globally (instead of just within the country).