The .co registry has issued an open letter regarding the registration of .co domain names that might infringe on trademarks held by companies.
If you are considering registering a .co domain name then be sure to check with the USPTO.gov for any trademarks that may be held on names of interest.
The .co registry announced that there will be no refunds on names registered in violation of a trademark regardless of how much you paid for the domain or how you acquired it.