how much do you like your sight? enough to watch it shatter cause someone "out downscoped" you in a skirmish? ... nahh it was probably just a lucky shot, but still!, i know i wouldnt take the risk. its simplistic design makes you slap your head and say "why didnt i think of that?!" the price is like any warranty, too steep for something that might(not) happen, and for its minimalistic design. i think more people would buy it for a price between 5-7$USD but if the set price is 10$ to protect my scope/red dot i'll do it. thats one mans opinion though.
it flips up when you need it, and down when you dont. switch to yellow if you like that summertime look down your scope/sight, and NO it does not effect your down scope vision in any way... well at least not in my eyes ;)