Mine came with the bike, and is absolute crap. It's mounted to the bars, yet I've had no problem with shorting. It does have a cap to go over the socket when not in use though.
Best solution? Fit where you want, and add a 10A fuse (or less). NO 12V appliance will draw that much, so if the worst occurs, you lose a 20p fuse, not a £200 alternator!