Related to this, there was a series of 'solar telescopes' being sold as Childrens Toys a couple years back (unfortunately I can't find the original article now) which was very dangerous because the usage was such that you use your eye on the telescope to view the image (rather than reflecting off a wall, which is a much safer practice) and the solar filter inside was very easily dislodged - not attached all that well. In the event it happens, you can say goodbye to your eyes :(