- Miners running out of ore (always important, since you can't place them like this)
- Radars that just finished discovering new land (ignoring ones placed without any land to discover, or ones that haven't had land to discover for 15 minutes)
- Manual-mode power switches in the off position (maybe after a couple minutes of being off)
- Train in automatic mode with an active schedule either has no fuel or can't path to the next station (might actually be very bad, but we don't know how each factory runs)
Alternatively, just a notice to let players know mining drills are empty would be nice. Repeatedly checking on mining outposts to check if that one mining drill has run out is tedious.