To be able to auto-ban botters you have to find a footprint that it leaves.

If you ban someone because they craft non-stop for 10 hours, that doesn't always mean they are a botter. You would then be banning people who actually did craft for 10 hours.

A lot of games suffer from this problem.

A footprint typically has to be very logically deep. To get a footprint that deep though, you need time and data.

Look at All Points Bulletin. They have actively said they have been monitoring and ALLOWING aimbots, purely so they can create a footprint for bot-detection.