The Red Cross symbol (a red 'plus"? symbol on a white background) is protected by Canadian law. The Canadian Trade-marks prohibits anyone from adopting the Red Cross symbol in connection with their business, as a trade-mark or otherwise.
The Red Cross is currently contacting members of the video game industry regarding their use of the symbol in video games"?especially violent games"?and asking them to stop using the symbol. Details of the Red Cross's concerns are available here http://tinyurl.com/7sf45