I have no reason whatsoever to disbelieve this article. However, having said that, I have also seen photos of President Obama doing charity "work" in clean crisp clothing that suggested he did about two seconds of work before the cameras shutters flew, and stopped two seconds after they stopped.
That's the key... check the clothing in the photo. I once saw a photo of Tyra Banks painting for some ghetto rehab project, yet she was all done up, dressed fashionably, and didn't have a speck of paint on her. On the flip side, I once saw a photo of Paris Hilton (imagine that!) doing something similar, and from all the paint all over her it was clear she had been actually painting.