http://www.wipo.int/amc/en/domains/s...?domain=google
As you can see....VERY few cases...one was Netzero which held a lot of names and it looks like they gave them up easily. The rest are names google would want to have like wwwgoogle.com and GoogleGear.com.
If Google had a problem with your domain you would get a C&D with an option to give-up your domain in all likelihood. The problem with having a good Google domain is that if it does become a success it will most likely be taken. And no one will want to buy it. So I don't see what good it is to use a Google domain in the first place.