Happened to take a look at the source stats on one my client machines that is using the NTP pool, and was surprised to find the PTR record of one of the pool members I was polling indicated it was a DHCP pool residential Internet service IP (specifically a Verizon Fios DHCP residential IP address).
Joining the pool using a dynamic IP address seems to me to be a bad idea as the IP could change at any given time. Some ISPs do not regularly force their customers to a new IP lease (for example, Verizon Fios is commonly known to not regularly force IP lease changes), but a simple power outage or connection issue would lead generally lead to a new IP lease.
Is my thinking wrong? Is this something that has been discussed / decided previously and was decided to be okay?
If not, would it make sense to perform a PTR DNS lookup when someone attempts to add a host to the NTP Pool, and if the PTR contains certain keywords (i.e. pool, dhcp, dyn, dynamic, etc.), not allow the IP to join the pool?