Yeah... Not some people though. For example, I generally have MC open all the time when I'm using my computers at home. I don't always have it actively doing anything though, and I use my keyboard buttons to control a wide variety of other applications: Media Player Classic, ZoomPlayer, WiMP, etc, etc, etc... It's generally considered bad form for an application to steal control of global hotkeys (which is essentially what those buttons are) when they aren't the foreground application. If this feature is added (or exists already) in MC, it should certainly be optional and not the default.
Now, that said, I'm not sure that this is how it works, since my buttons are controlled via Girder on the machines where I actually use them regularly. I use those buttons for all sorts of crazy things. For example, I have the FF/RW buttons assigned to the Text Zoom feature in Firefox (and Stop assigned to Stop, Play assigned to Reload, ec). I also use them in Photoshop for zoom in/out/pixel-level, and in many video editing applications. But, when a video game (such as my ZSNES Super Nintento Emulator) is in front, then I have those buttons routed to MC so that I can change the song playing.