UnitRestricted has several bugs:
1. The Wolf in NanoBlobs is restricted to 0, no matter what I set it to. Please tell me that is the result of some testing code and not some bizarre bug

2. It should be documented that you need to set the value to 0 in order to limit it to 1. Not exactly intuitive, but meh.
3. I could queue multiples of a given unit, even after it was restricted. I should note that I couldn't build the unit- that part works just fine. But AIs will probably go bonkers, sending out commands to build things they are no longer allowed to. Perhaps the smarter AI designers will search for these values themselves.
Overall, this is an absolutely awesome feature, and I'm very excited about it. It may seem like a fairly lame thing, but it's not- it'll make game-balancing the most powerful things a lot easier, and give game designers a good tool for keeping certain things from getting out've hand, both on offense and defense. Great stuff.