I hope you weren't being sarcastic/kidding about the galvanic corrosion because I'm going to feel pretty stupid if you were. I emailed a BD Rep about it cause I'd rather not have my slings breaking. Here's what he said:
Where did you read such a thing? BD does not use any such 'coating' on any of its quickdraws so it's a little difficult to comment. I've actually never heard of this. Make sure you're getting good info.
This rubber 'ring' actually has to do with holding the rope-end biner firmly in place so it doesn't flip around when you're trying to clip it from a tough stance (it's quicker, easier to do, etc).
It's perfectly fine to use Quicksilver or Oz Draws and/or Carabiners for any style of climbing/mountaineering use.
(This post was edited by keep_it_real on Jan 5, 2009, 3:52 PM)