As I mentioned earlier, you have nothing to worry about - we don't touch your repos! Unfortunately the read permissions we need are classified as "write" (or at least we couldn't find a way to specify them as "read" in our very limited time).
Once everything settles down we are going to think about ways to make it easier for people to use and trust the service so that they don't need to worry about permissions or anything like that.
Thanks so much for your input, we'll definitely take it into account!