Me and others used to receive almost daily telemarketing calls. Once you enroll in the list and get the confirmation, you notice a drastic reduction in calls, and get maybe 2-3 per month. If you at that point start saying that you're on $NAME_OF_LIST to the companies who do still call, they say sorry, hang up, and you get less calls faster. This been the experience for 10+ people and myself who've used to get these calls, and no longer do.
The way the companies manage the lists, is basically that they have three types, they have huge unranked/unchecked lists of just numbers, one list of "good" numbers that are at least online, not on do-not-call lists, haven't recently been sold to already, and so on, then the group of blacklists essentially. Whenever the telemarketers work in their stations, the only numbers that even get dialed by the central robot for them, are the "good" numbers they've been assigned for their shift.
The way the companies manage the lists, is basically that they have three types, they have huge unranked/unchecked lists of just numbers, one list of "good" numbers that are at least online, not on do-not-call lists, haven't recently been sold to already, and so on, then the group of blacklists essentially. Whenever the telemarketers work in their stations, the only numbers that even get dialed by the central robot for them, are the "good" numbers they've been assigned for their shift.