We spoke with PopCap about the issue, and they told us that yes, they run a program called luasrcdiet on their code to shrink it down and keep the memory footprint to a minimum. While working on their addons, they were in contact with Blizzard (and showed them the original, non-obfuscated code), and they tell us that Blizzard decided that since the purpose of the obfuscation rule in the policy was to allow the community to police their own addons for bad code (and since Blizzard trusted PopCap, there were no concerns there), then Blizzard was OK with PopCap releasing obfuscated addon code.
So. Has PopCap broken the rules? In the strictest sense, yes -- the rules say no obfuscated code, and PopCap's addons do make things hard to read. But Blizzard, who wrote the rules to begin with, has no problem with making an exception for PopCap, and in doing so, their reasoning seems pretty sound. It doesn't seem fair to make an exception in any case, but we admit, if you're going to make an exception for anyone, you can't go wrong with PopCap. What do you think?