it's not overkill if that's what you shoot with....if you're not going to use it what's the point in owning it,
tha last time I was at WDW I walked around with 2 Minolta 9000's around my neck, one with motordrive one without, plus a minolta point and shoot, just in case...LOL
and a camera bag on my shoulder...if you're used to carrying that kind of gear it's no big deal,
as far as using it on rides...I've taken my 9000's on hundreds of rollercoaster rides, without damage,, strap around neck and both hands on camera, no need to worry...if a ride gets too wild, hold onto the ride with one hand and cradle the camera against your chest with the other.
as I stated earlier, I have since discovered the advantages of a good photographers vest, everything fits in the vest no need for a bag and everything is at hand, I like my vest so much that I just bought my second one last week, I now have a khaki colored for warm weather, and I just got a black one for cooler weather use.. I stumbled upon 2 places to get them for half the price of most photot stores...