Policy Statement on Address Space Allocations

I still do not see why you insist this is providing free transit.

If you're a backbone and connected into the area, within your network
you advertise the /8 outside the area and the details within the area.
If you're a backbone and not connected into the area, people can
advertise the /8 to you and provide transit, or not, per existing
peering and transit agreements. If you're a small provider within
the area, you can talk to everyone else in the area and to the
customers of backbones which come into the area. If you're a small
provider outside the area, you probably buy transit to the area from
your backbone along with transit to everywhere else.

Everyone would probably want to special-case the block in router
filters to make sure that they weren't being unintentionally used
for transit by people who aren't supposed to use that route, but
the upside is that those faraway routers carry one instead of hundreds
or however many routes.