Some cameras place lens correction data into the EXIF fields that some raw converters will automatically pick up and use. The problem with that, of course, is that you're starting with your image having altered pixels, and you may or may not like what happens with that.
The developer of AccuRaw, Sandy McGuffog, has come up with a small tool that can help you remove those lens corrections. Basically this works by converting the image to a DNG image (if it isn't already in that format) and running a small DNG Cleaner utility. The DNG Cleaner removes the opcodes that are in the EXIF and then applications like Lightroom and Photoshop ACR no longer apply them automatically.
Unfortunately this is just another workflow step that didn't need to exist (Adobe, for example, could just have an Apply Lens Corrections Automatically preference). Why we keep getting additional workflow instead of simplified workflow is a story for another day.
And if that weren't enough, Sandy has another small software program called dcpTool. This is a trickier program that requires some color management knowledge on the part of the user to take advantage of. Basically, this allows you to decompile DNG Camera Profile files into readable form, and recompile them back. But the thing that makes this little utility interesting is its ability to remove Hue Twists, something that a lot of camera makers do with color.