I can't believe two people who had a chance to get the MX Deep Star keycap didn't pay up. I might as well start my WTB thread here shortly!
It's so hard to know with these things. Who knows what could have happened with those folks between entering the forms and getting the shipping invoice - hopefully nothing bad. Almost happen to me once when my phone decided to be a POS and stopped getting email pushes for a couple of days. All in all tho 10 drops out of 150 isn't' too bad ¯\_(ツ)_/¯
Some time ago, I entered an artisan sale when I had more than enough funds. Didn't see the invoice until late in the night, but decided to wait until the morning as I was too tired.
Woke up, saw some dude on eBay issued a chargeback that put me in the negative, and couldn't pay the artisan invoice until a few days later when I cleared up some funds. 
That kind of stuff is understandable, but honestly, this is probably the cheapest price you are going to get an artisan cap for. Hopefully nothing bad did happen to these people, but it seems with as cheap as these caps are that they would be able to swing the max of $14 to get the cap to them. Either way, their loss is another person's gain
I also didn't mean it to sound like I am talking down to these people, it was rather amazement that the most popular cap, with almost 3x the amount of entries as the next most popular cap, had people who won but didn't pay.
