Actually, I think all major providers use automatic provisioning systems
which generate router configs. They don't need to rely on router vendors to
set particular defaults. If all major providers made sure their
provisioning systems turned off directed broadcast, a lot of the problem
would go away.
So "Router defaults" is a lame excuse for ISP's. Even little ISP's have a
list of things they have to setup, (eg ip classless, subnet zero, etc)
which have "legacy" or otherwise inappropriate defaults.
And yes, some customers may in fact want or need directed broadcasts on.
For example, if they are subnetting. In that case, you change it for them.
I tell our customers certain things are turned off by default, and if they
really want it on, they will need to ask.
Of course, the problem remains that some smurfers are undoubtedly on this
list, possibly working for major providers. (This is my guess as to source
of the 10.x smurf amps.)
--Dean