Cloaking should be opt out, not opt in. Because even if you go through the process of begging for a hostname cloak, there are many scenarios where the cloak is temporarily not applied (netsplits, or if NS lags and your identify happens after joining your channels) and oops the IP leaks. This is unacceptable. It should default to privacy.

The fact that server operators of many (all?) networks refuse to enable cloaking by default just shows that IRC has a very different culture than what modern users have come to expect.

In my mind there is no reason for cloaking to not be enabled other than "it's always been that way and I like seeing ISP hostnames when people join!".