On my 1995 Z28, my low coolant warning light went on. I added coolant, it took about half the container, half a gallon (I think). The light still goes on and off sometimes. Is this a bad sensor, or do I just need to take it to the shop, plug it into the computer, and reset the coolant warning thing?

 

The low coolant sensor is prone to problems. If you unplug it, there won't be any consequences other than the light will no longer work. It does not report anything to the computer, so no problem with that.
If you want to retain it's use, replace the sensor.