I assume that CNAM lookups on not-in-service numbers don't currently return anything useful, like "Not in Service" or "invalid number"?. So why don't they? Can they?
I've been seeing an uptick lately on getting calls from my area-code+nearby-exchange that turn out to be not-in-service numbers, and these seem to happen after a run of 3 to 10 blocked attempts from well-known fraud/scam CID's. These not-in-service calls last only a second or two and seem to be designed to check and see if my number is indeed active.
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