They could. And cheaters using "sensor hacks" or "map hacks" can't be detected server-side because those hacks just provide information to the cheater client-side, without actually affecting gameplay directly (they don't alter the cheater's speed, aim, etc). But the way to beat those type of hacks is to minimize the amount of information the server sends to the client. If an opponent is just around the corner, then that fact shouldn't be transmitted to the client until the client is just about to turn that corner. So the client-side "sensor hacks" aren't very useful in that regard because the cheater isn't actually receiving extra information until it's basically too late to act on it.

But here's the thing. The goal is not to detect all cheaters. That's not really possible. The goal is to eliminate all seriously disruptive cheaters. For example, the guys who run around with a speedhack plus an aimbot and annihilate every opponent in just a few seconds. That would quickly ruin the game, so those are the most important type of hacks to prevent. And I could just let the community report each offense then ban the cheater afterward, but that doesn't really scale, and at that point the cheater might have already ruined the game for a lot of people. So it would be advantageous to implement a way to detect cheaters realtime.

The server-side anti-cheat code would remain closed-source, so it wouldn't be known which probabilities were being monitored. Other parts of the server code also have to remain closed-source, actually, because otherwise people would be able to examine the game's rules to gain tactical knowledge. (i.e. a player could read the game rules source code to learn where and when creatures will spawn, then that player would go around and camp all the right spots to gain maximum benefit.) However, that's a fundamentally different motivation for keeping the source code closed. At that point, it's not closed because we're worried about the competition; it's closed to ensure that the game will stay enjoyable. So that type of thing doesn't seem like it would go against the spirit of open-source.

Consider this -- if people are cheating by pushing their statistics to the point just before they would get banned, then those cheats don't actually impact other players very much, because the cheater's statistics are still within acceptable ranges. At that point, the cheaters are using the cheats so infrequently that they don't statistically affect gameplay. So in that regard, it isn't necessarily worth the extra effort to stop them, because the goal of enforcing reasonable gameplay statistics has been achieved, so the overall game experience is mostly fine from other players' point of view.

Also, your blog posts are great. Please keep on writing them. One specific part of your writing I'm interested in is this:

"Increasing my effective working memory has an impressively super-linear effect on my problem solving ability, how fast I can learn things, and also how much fun I’m having."

I have working memory problems, so it would be really fantastic to learn how you improved yours. I didn't know it was even possible to do that.

My working memory improved with a simple idea: get other things to remember for me. :-) Paper and machines do a great job. Tabs in particular are a way to expand one's working memory; the browser can keep track of what you meant to check out or do, leaving you to think about other things. This takes discipline, though. Also, I find I can store some things in muscle memory; if I've copied some text for example, I feel like I'm holding something.

With deliberate practice and the right techniques, people can learn to expand certain areas of short term memory by associating it with other, more solid knowledge. This used to be called 'chunking', but the process seems entirely different. There was a paper (referenced by Ericsson et. al. on expertise) on a group that increased their digit span memory from 7 to 80 in just a few sessions.

Some people (e.g. Ericsson) think that with deliberate practice and effort, experts route around the standard short term memory entirely: in a blink they can remember information just presented to them, in a field that they know about, in the long term. For fields outside their expertise this ability doesn't kick in, however.

For other readers of this thread, there's also this, apparently.

"Improving fluid intelligence with training on working memory"

http://www.pnas.org/content/early/2008/04/25/0801268105.full...