Defining MOAs vs Restricted Area
I find that many Private Pilot applicants and not a few already-certificated pilots are confused between Restricted Areas and MOAs and how they behave.
A MOA (Military Operations Area) is an airspace where there may be a higher than normal concentration of military aircraft flying around. The difference between an MOA and a Restricted Area is that in an MOA the military aircraft are just flying around practicing formation flight, intercepts, and the like, but they are NOT shooting guns or dropping bombs. In contrast, a Restricted Area often encompasses a gunnery range and/or a bombing practice area. Dangerous stuff goes on in a Restricted Area. That's why you don't need to call anybody to fly through an MOA, but you have to call about a Restricted Area (see below). According to the Airman’s Information Manual, in order to fly through an MOA you are supposed to be "extra vigilant", but you don't have to call anybody to determine if it is active or not.