How is this any different from having a phone number that's just one digit away from another sensitive one?
Well nobody has the phone number 912 for instance. We specifically make sensitive numbers distinct from "regular" numbers. 911, 411, 311, 999, etc.
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The North American Numbering Plan specifically reserves numbers to forbid that (to the extent that the DTMF for 1 is actually handled differently by the line discipline, or at least was 20 years ago)