Mt Spokane Photography said:
They claim that it prevents damage to a lens. I don't see how that's possible
Found my old YES-my-filter-saved-my-lens documented samples (there are lots of such forum threads around). It is as often the barrel as the front element which is saved by using a filter.:
http://photo.net/canon-eos-digital-camera-forum/00a2LF
http://www.flickr.com/photos/robbie_ewing/4997119140/
http://neilvn.com/tangents/2010/02/27/using-filters/
http://blog.production-now.com/2010/11/uv-lens-saved-my-camera.html
http://community.the-digital-picture.com/showthread.php?t=1223
http://photography-on-the.net/forum/showthread.php?t=169640
http://www.fredmiranda.com/forum/topic/33631
http://www.flickr.com/photos/enfo/5460898319/
http://www.flickr.com/photos/bibbit/2771036799/
http://www.flickr.com/groups/tokina124/discuss/72157623441192917/