I am an insider. I signed up the first day. I didn't get a birthday voucher. I am going to look into why I did not get one. Thanks for the information.
I noticed during my birthday-month (birth month?) that I didn't receive any email or card from Coach. I used to get one from my regular sales associate, but they had sinced moved on. I logged in and saw under 'my profile' / 'my rewards' my birthday voucher was there. So it very likely only shows up if you login and look for it in your rewards during your birth month*, but they don't send out an email. Probably to keep from having codes shared.
*My bday is in the middle of the month, so it's possible that it's not birth month, but a few weeks before and after.
I also received a $20 voucher for a recent purchase and a merchant credit for an issue I had with another purchase. Those only show up in my email and not on my coach 'insider account'.