There is a sensor on the brake cylinder cap that detects low brake fluid level. The quick fix is to add more brake fluid. But because it is low, you want to check your whole brake system for the cause. Worn brake pads, worn rotors, and leaks in the brake system can cause low brake fluid levels.

In my experience brake calipers occasionally seize unpredictably and there is probably no specific preventive maintenance. On European cars I've had I would say I replaced on average one in the time I owned each car (about 6-8 yr). These cars were all bought used. I have replaced calipers much more often on used Japanese cars - but I do not think there is any particular reason for this (maybe lack of maintenance by previous owner).

In inspecting the brakes I would not worry much about lubricating the caliper pins unless the dust boots have cracked, in which case, replace the boots and lube them right away. On many cars the caliper assembly partly floats so you can feel if it is able to move freely on the slide pins. If the dust boot on the caliper piston itself is not intact, water and dirt will get in and seize the caliper for sure but this is hard to check without removing the caliper. This boot would not likely fail before you need new pads, unless it was installed incorrectly from the beginning.

An Acura I had listed so many maintenance items to check (and so frequently) that I think they must have been marketing to customers who would regard car repairs as a fun pastime.

I beleive theyre refering to a "visual" inspection. You know, check pad thickness, condition of hoses, fluid level in master cylinder, etc..