Actually, some of the IP addresses get reused multiple times, so apparently from a finite pool of addresses.
It's having to re-use IPs, so the pool of addresses is likely finite.
Perhaps BV could determine the set of addresses by their max / min values and block the range for a few hours?
Not impossible. In which case, the BO needs to kick some ass. I'll BV if he needs manpower that won't (deliberately) fuck things up.