[wrs]

My rule on edge cases is: It's OK to not handle an edge case if you know what's going to happen in that case and you've decided to accept that behavior because it's not worth doing something different. It's not OK to fail to handle an edge case because you just didn't want to think about it, which quite often is what the argument for not handling it boils down to. (Then there are the edge cases you didn't handle because you didn't know they existed, which are a whole other tragicomedy.)