After recently becoming another statistic by making a mess of a 2.5 drive (inserting a 3.5 adapter wrong way round) I suggest that anyone using one should put a fuse on the adapter on the outgoing 5v line. This way if the incorrect pin is grounded this fuse will hopefully blow first.
Simply locate the 5V track coming from the power adapter, cut the track, and place a fuse across the gap (I have gone with a 1A fuse, which may not be enough) time will tell. The drive itself has a 2A fuse, so I wanted to go below this. Maybe feedback from the rest of the group will determine the best value to use here.