Binocular ownership figures? Relevant to 4th amendment

Hi, I have a question about the history of binoculars, and would really
appreciate your help. I am in law school and am researching the use of
binoculars in conjunction with a U.S. 4th amendment case. A recent case
in particular states that there is no search (hence no 4th amendment
violation) if the surveillance equipment used is in common public use.
An older case (this one from the 1970's) says that binoculars are not
widely in public use and are "sophisticated surveillance equipment."

My tenative argument is that while in the 1970's, binoculars may not
have been in wide public usage, probably due to the fact that they
would have been more expensive, in the present they are commonly used
by the public, and that is supported by the fact that they are now less
expensive.

So, I guess what I'm asking is - is my argument correct, and do you
have any figures on ownership of binoculars (70's vs. present) and
perhaps general price comparisons for a good set of binoculars (70's
vs. present).

Thanks very much for your time,
Robert