The LIDAR Compass fires two separate lasers in a bunch of directions, which calls to mind some concerns about eye safety. How do we make sure that, in the course of normal operation, we don't accidentally blind anyone?

You'd be right to guess that a safe bet here is to just use a low-powered run of the mill red laser diode. Unfortunately, red isn't, in my testing, especially visible after getting flung around and spread into a big circle by the spinning mirror. Green would be a much better option.

Green laser modules are very cheap and plentiful, but it's VERY hard to get modules that actually do what they claim. The "laser enthusiast market" being the primary consumer of such modules, most that you can find output WAY higher power than they say, and also omit other safety precautions that add up to extreme non-eye-safety. In particular, the ultra-common and high-brightness 532nm green lasers all over the internet are DPSS - diode-pumped solid state. In this topology, an 808nm laser diode fires at one crystal that absorbs the 808 and re-emits 1064nm light, which then hits a second crystal that frequency-doubles that to 532nm. Because each of those two stages is relatively inefficient (something like 20-30% end to end), there's a ton of leftover 808nm and 1064nm laser light coming out the front of such lasers, and when they're built down to a price, they often lack the optical IR-cut filter to remove those frequencies.

Making matters (much) worse, when those crystals are too cold, they no longer work. So if the device overall is too cold, it'll appear off, while outputting still-blinding invisible IR laser light.
The solution we've settled on to get around these concerns is to simply pay a little more for a diode that 1) operates at 520nm, with a direct-emission source (no invisible byproducts), and 2) at the power level it claims of <1mW.
Luckily, this still produces a bright-green dot that should be visible even outdoors on a job site.