Not sure about the 75% figure thrown out there.....I have to agree with Martin, I don't think so either.
With that said, I am an active member of my ARES group and have been since I got my ticket almost a year ago. I have no ID card issued to me from ARES, so I don't know, what ID you speak of?
As far as the plates, here in MO you can apply for Amateur Radio vanity plates, by simply paying a $15 dollar fee, filing an application and signing a form swearing that you have a valid FCC issued call sign and that it is not currently revoked or suspended and in good standing, along with a copy of your FCC license. The plate uses your call sign instead of the usual random numbers and letters non-vanity plates use and underneath states "Amateur Radio" instead of "Show Me State". I requested a set a few months ago, unfortunately I have yet to receive mine. Here in can take up to two months to receive them......I keep joking they need to light a fire on our prison convicts and get my plates out to me.
As for the reason.. I am sure they are many with each individual operator, for me it was simply a matter of being proud of my call and wanting to identify with my fellow HAMs when I am out and about. As I doubt, anyone who is not a HAM will know what the heck amateur radio is, much less what the letters and one number on my plate mean.
Will it generate calls from other HAMs while I am driving around....maybe I guess. I'll have to wait and see.
Of course it will only be a matter of time before the "black helo" believers chime in, who will say we are all idiots for advertising our calls, our names and where we live on our license plates, etc.. :roll:
To each there own, if someone wants to find you they will....my HAM vanity plate will not make it any easier. And if it does, oh well, come on by, I live in a town of 10K, most everybody knows who I am, what I do and where I live anyway. I am not trying to hide. I can't, even if I wanted to.
So, come on already convicts.... getter done, I want my plates!