I've seen this discussion several times before on other forums. Experimented with it a bit on my own cameras with both red and green lasers (your basic consumer-grade 5mW types). A couple things:
1. It's not the laser hitting the sensor that disrupts the overall image, so much as the flare created within the lens optics. If the laser hit the sensor directly, there would only be a single bright spot.
2. As the one post mentions above, you would have to hold the laser VERY steady. It's practically impossible for most people to hold it steady enough to blind the camera constantly, let alone to do any damage (assuming you could hold a laser that's powerful enough; I have no idea how physically large such a unit would be). If you wanted a camera to STAY blinded, you'd need to put the laser on a tripod or C-stand to something. And keep in mind, the further you are from the camera, the more the laser movements are amplified.
3. Keeping in mind item 1, it's also not necessary to shine the laser directly down the center axis of the camera to blind it... in fact, if you JUST want to blind it, it's more effective to shine the beam onto the front element of the lens from a slight angle, thus increasing the flare.
