Not quiet ammo related but I used to work for a company that would ask for a details with a purchase. Anything under $100 we could just flick through without entering details. Over $100 we had to enter something.
The reason we asked was if you bought something (phone, TV, Computer) and you bought it back, "I broke it but I don't have the receipt any more" for warranty stuff.
It was a large NZ wide company with two chains, Bond and Bond and Noel Leeming. And you could walk into any store and say "I brought this in X at Christmas and it broke" and we could punch in a phone number bring up the receipt to send it away for warranty from there, without having to return it to the original store. No data mining or anything nefarious but just for record keeping.
If we got customers coming in purchasing who did not wish to give data we used to use the store phone number and the name "Cash Sale". The only time we HAD to enter real details was for returns. This was due to fraud stuff. e.g You steal whatever for store X and return it to store Y but "lost the receipt. Can I exchange it?"
Now I can understand people being ticked off for firearms stuff but here's my thoughts on that matter. At another job (sporting goods) we had departments and dissections e.g 47/03 was Hunting/Ammo and that was as specific as it got. The tag might say ".223 Rem" or ".177 Pellets" but the till would only know it was "Hunting/Ammo" with a cost price of X and a retail of Y. A sling would have been 47/04 (Hunting/Accessories) along with bipods, decoys etc.
So I wonder if they have just gone "Boom" and put an "Enter DoB" flag on a dept. without completely considering what it would encompass.
Secondly, it's your DoB. AFAIK there is nothing identifying about that. I can see asking for DoB if you were buying a knife etc but agree that it's a bit stupid for a scope. At a push, "Excuse me, Sir, can I see some proof of age please?" I know supermarket tills here when you buy booze come up with a "Sight ID" warning that requires a supervisor to clear but most of the time they just look at me and go "He's over 18" and just hit "ID sighted"
One thing that has just occurred to me is the Human Rights Act (as odd as that sounds) Let me explain. A 50 y/o goes through and the "ID sighted" button is hit because he's quite obviously over 18, I go through (I'm 22), once again the "ID sighted" button is hit. Then an 18 y/o goes through. Cashier asks "What's your DoB?" "Well the other two didn't get asked so you are now discriminating against my age" which is against the Human Rights Act. As ridiculous as it sounds its that easy. You cannot discriminate anyone. In my job at a bar, if a pregnant women comes in, I can refuse to serve her alcohol (because of the risk to the baby), but if I say "I am refusing to serve you because you are pregnant" that's discrimination, even with all the evidence supporting Foetal Alcohol Syndrome
If you are shopping anywhere, and are asked for similar, just use the following details.
Cash Sale
1060 West Addison Street
Chicago, IL 60613
(773) 404-2827
and make up a DoB.
If they insist on seeing an ID show one but ask that another DoB is entered if necessary.
Sorry that rambled along a bit but hope it is food for thought