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Will these 141 organizations many of whose business relies on BIND be eligible for your fee-based list? Do they consitute providers of "critical infrastructure" in your eyes?

No. 90% of the name servers on the Internet fit that classification. "Restricted notification" is not practical on that scale.

Considering that they have a positive revenue model (vs TLD registries that don't, or have negative revenue models) I would suggest that they pay for it and help support ISC/BIND.

Of course, everyone should support ISC. And the Sierra Club for that matter. But "should they support ISC?" is a completely different question than "if we don't get them upgraded before the whole world knows about it, are we doomed?"