In 1999, I was trying college for the first time. (It wouldn't end well, but that was another story.) I was still a Duct Tape Sword Guy, so I had a smallish duct tape sword. It had become a little battered, but my dear friends BJ and Shawn had given it to me, so it had sentimental value. One night I was up late, hanging out with the midnight crowd down in the lobby. I had my duct tape sword with me.

"Hey, can I see that?" some guy asked. He seemed friendly, I'd seen him around, and some of the other guys had had a go with the duct tape sword. I handed it over.

He snapped the duct tape sword over his knee and walked off.


In 2003-ish, I'd broken up with a boyfriend but we were still on good terms, and I'd made friends with lady he was seeing off and on. He babysat for my roommate's kindergarten-ish age kid when there weren't any adults of the household available. He sometimes played around on my computer while he was over.

One day his lady friend IMed me to let me know that while he was on my computer, he'd seen a chat log between her and me that I'd saved to my journal (as was my habit, since I made up for a somewhat flaky memory with electronics, and my journal was the least likely to die a horrible electronic death). He'd read the chat log, broken into her journal, given himself access to a filtered entry of hers, left a wounded comment on the entry, and showed himself out again.


Some years ago, I was having a casual conversation with a close friend. The topic of a mutual mentor came up. "Do you think he's a good man?" they asked me out of the blue. I replied, hedging slightly over a particular character flaw, but I eventually said that I thought he was a good man.

My friend sort of drew up short. "... You don't know," they realized.

At which point I learned some things about this mentor which I will never unlearn.



I thought the social contract would protect my sports equipment. I had no clue that my ex-boyfriend would betray my trust to betray his girlfriend's trust in that way. I had never dreamed that this mentor would have done anything of that sort or to that scale.

I was looking, just now, for the account that someone I know wrote about a conversation she tends to have with friends with kids. The toddler is reluctant to interact, and the parent encourages, apologizes. "Oh, no need to apologize, it's healthy." "Oh, it's not like you're a stranger..." "Fun fact-- ... oh, you didn't know..."

Humans tend to hold on hard to the idea that since you can spot some untrustworthy dickweeds from a mile away, it follows that you should be able to spot most untrustworthy dickweeds with enough observation and vigilance. Never mind that false positives crowd the field, and people are quick to reassure you: Oh, he's fine, he's my friend, he's okay, I'm safe around him so you're safe around him. Never mind that sometimes it's just chance, and a disinclination to carry textbooks, that keeps you from being alone and unobserved in the presence of the wrong person.


Every assessment of trust I make carries two values: my trust of that person on that axis, and my confidence in my assessment.

I trust that this dude will not be extraordinarily reckless with my sword; he probably won't use it to stab passing strangers, but he might whack at me or these guys a bit. Confidence: well, I've only seen him in passing and for a grand total of about 5 minutes, but he doesn't look like a jerk. Call it 60%?

I trust that my ex will take good care of my nephew, and won't allow the apartment to get trashed while I'm gone. I trust that he won't install malware on my laptop. Confidence: we were together for a couple months and I still wanted to keep him as a friend even though the spark wasn't there, so 95%.

I trust that this guy will be a good mentor and teach my group lots of important things about technology. He will probably not straight-up murder us, if the class pisses him off we'll have enough warning to get out of there. Confidence: there have been no previous reports of murder, and he seems friendly when he's having a good day. 80%.

I was right. He didn't stab anybody with my sword. He didn't neglect my nephew or let the cat trash the apartment or install malware. He did teach us a lot of things, and he didn't murder anybody. And I never saw any of it coming.


There have been plenty of people who showed obvious warning signs, and some of them, I never offered the chance to betray my trust. Dude with a history of cheating, perhaps we should not date. Dude who is making various generally violent comments and leering at me on the bus, maybe I'm not going to show you what my actual bus stop is. Girl with the history of bullying, like hell am I going to tell you something personal about myself just because you asked me.


It's the ones who surprise you that you worry about, after.

So there I am at work, and there's a thing and it looks like a little red flag, waving in the breeze. Not a big one, not the sort of banner that you can grab a handful of and wave it at all your friends and say "This is a flag, it's made of nylon or something, it's really shiny and thin and bright red and it will wave in the breeze if you can find a pole to run it up. This is a flag, and it's red." Just a little one. It might even be orange, or brown. You can't quite tell.

What if he turned out to be untrustworthy? says the back of the head, listing off the times that someone with no apparent red flags fucked up your life, for hours or days or years. What accesses does this guy have? What are his powers? How easy would it be to defeat him? You discount the protestations of trust from people who know him, even if they do have a pretty convincing reason for that flag to be there legitimately. You once defended someone who proved themselves unworthy of it. Some people may hide the flags around their friends, and the ones who hide it are more dangerous, because they know what they're doing.

What's the realistic worst-case scenario? the little voice presses. How screwed are we?