Quick question, do I have to EARN the voucher, or USE the voucher in order for them to be valuable in the BoS bunker? The wiki is a tad unclear on this point..

Earn them, You can get one by reaching the max amount you can win at the casino.

You have to win 7,500 chips at the Sierra Madre casino to get your first voucher. When you've done that and return to the Mojave, you get new vouchers good for 1,000 chips each in the bunker drop box every three game days.

I have a somewhat relevant question that it seems appropriate to ask in this topic.
-Do the Sierra Madre awards (the cips and vouchers that spawn in the bunker safe every 3 days) build up, like if you do not pick them up for 9 days will you have 3 vouchers or will there just be one?