The type of music festival was not mentioned. We are fairly avid bluegrass festival followers which are often held at places which are dry camping only. Somebody running a noisy open framed genny is the rare exception.
Now, the big country or rock festivals may be another story. Looked at attending one this year. Much more expensive. Far more people. Not really our type of scene so we did not bother. Can't imagine the camping area being much different than at a bluegrass festival where people mostly have inverter gennys & keep the use to a minimum.