Oh, and I should also clarify that your "reclaim" issue is even more complex than I discussed. It doesn't matter if you forget to remove the forwarding number or not, when abandoning service with that provider. Since the number was previously used to create an account, the next user can't use that number to request a new GV number, although they CAN use it to add as a forwarding phone to an already-created account. In that scenario, the user trying to use it again will receive a warning that the number is in use on another account, and would they like to reclaim it. Since they presumably have working phone service on that number, the safeguard is that GV will call them on that number to verify it, and allow it to be reclaimed. This reclamation procedure is limited; there is an undisclosed number of reclaims permitted (the "innocent purposes" reclaim) before it's banned, too.
This is also the only fix for the Craigslist scam: someone pings you via Craigslist email, about an item you are selling. They tell you "I'm using a special phone system that requires you enter a two-digit code when I call you to discuss your item. Please enter the code when you hear the message." This scam then assigns your phone number to the new GV number that the scammer is creating. The only way to recover from this mess is by creating your own GV account, using a different forwarding number, and then snatching back (reclaiming) your scammed forwarding number.
