Been reading this emotionally charged thread with a few giggles, until I read this. DOB is actually a piece of information which you want to protect. Think about it, when you have to prove to a credit card vendor, bank, Customs, or CRA your identity - one critical question they ask you is DOB. If someone asks for my DOB, I refuse - as I had an individual do on the EE once. PAL number, name and even address is fine when selling a firearm.
As a seller, I am very willing to provide information to the buyer as I will not release the (rifle in most cases) without the EMT or cheque clearing first. The information provided allows the buyer to know who I am and that I exist with the CFO.
As a buyer, unless I know, or have previously interacted, I check out seller by asking for PAL#, name and addy - then I EMT. Had wonderful experiences so far on the EE.