still more on that bug

I've gotten some more e-mails about the bug presented here for entomological inspection last week. Recent entries allow for an illustration of what is a good assurance vs. a bad assurance regarding whether or not that bug was a cockroach.

Good assurance, from a reader native to Houston, TX:

I come from the land of cockroaches ... Houston, TX and I want to
assure you of two things:
1) what you have found is not a cockroach
2) you would starve to death in Houston if you refused to dine where
cockroaches are present. The finest of restaurants have 'em, they are
in everyone's home. to make matters worse, they are HUGE and they FLY.

The person establishes cockroach expertise, offers a definitive ruling based on that experience, and then notes that things could be much worse if I was living in a place that I am statistically unlikely to ever live. Whatever infestations I might have here in Madison, at least I can think, that may be a large but but it's not HUGE and I certainly don't think it could FLY. Convincing and reassuring--so this reply earns top marks.

Bad assurance, from a reader in Pestilence, IN: (Basically something to the effect of)

"That's not a cockroach. I have lots of those kind of bug in my house. I don't know what they're called."

Hmm. Why I am supposed to take the fact that the bug infests this reader's abode as being prima facie evidence that the bug is not a cockroach, especially since the reader doesn't know what the bug that overruns their residence is?