I agree it "ought to be", but from a practical perspective, this often just isn't worth it at a local level. Actually determining the right cost for the extern

I agree it "ought to be", but from a practical perspective, this often just isn't worth it at a local level. Actually determining the right cost for the externalities would take a decent amount of work and odds are whatever the "fair" value is will be enough to kill the project anyway. The developer will likely jump to some other jurisdiction that isn't able to muster up enough political will to demand a fair deal. An outright ban might sound harsh, but there are benefits to their simplicity because many of these race to the bottom deals aren't worth engaging with at any level. Let some other community gamble with the winner's curse.