The Vixia G10 camera saves it's videos in an AVCHD wrapper. AVCHD was a pain in the rear for me, until i learned how it worked. To open this up without a program:
1) Plug the camera in (maybe I didn't need to mention this one haha)
2) When the camera pops up in Finder click on it
3) There might be a few things in this folder. What you're looking for is a file called "AVCHD". Right click on that and select "Show Package Contents"
4) The next folder may have a few things too, in this one you are looking for "BDMV". Right click on that and select "Show Package Contents"
5) Click on the folder named "STREAM" and you should see all the videos stored on that camera. Unfortunally they are saved as .MTS files which don't natively play on Macs (they do play with VLC, though). Most clients don't have to tech no-how to be able to figure out the right program to open that video file so I'd convert those .MTS files to H.264 MP4s if I were you.
Hope that helps!