DougW,
I wouldn't necessarily say that Volunteer Fire-fighting is done "on the side", I have been both a Volunteer and a Career(Paid) Fire-fighter.
And I just love the dedication and comrade-ship that comes from a Volunteer Fire Brigade(Department in the US), regardless of wether you are Full-Time or Part-Time, makes no difference, you are serving your community,and that's all that matters!
My Boss knows that, if my pager goes off, I have to be at the station, no worries and we regularly have a Dinner put on at a number of local restaurants, to say thanks for letting us attend these incidents, but,they know we are providing this service and I quite often, get paid, even though I am attending a Fire Call, it's all about working in together!!.