This is beginning to seem strange to me. OpenBSD has always had an "off by default" philosophy, a quality I have relied on since before 1998.
It takes little effort to enable aucat. Yes, it also takes little effort to disable it, however, unless (almost) everyone needs it, the approach has been to favor a cleaner, minimalist install. Let the population subset who want it make a deliberate decision to turn it on. Do not place the burden on everyone to decide if they need to turn it off. There are surely thousands on the list who have been silent because so many of us assume this is a non-issue. But I can only speak for myself. I would be disappointed if we turned it on, or if we included an additional burdensome install question. Sometimes disappointment happens, you cannot make everyone happy every time. So enough from me, but I have very (very, very) seldom ever been disappointed with anything in OpenBSD :) Warm Regards, -Mike