I didn't get any for my past trips, even when we stayed for over a week at AKL in a 2 bedroom condo, but all my past trips have been room only reservations.
However, I did get one for my upcoming trip next week. I'm thinking it has something to do with me either booking a package or using a bounce back pin code or a combination of the two. The jump drive came within 2 weeks or less of me booking the trip. I was really surprised as I've never gotten one before, I thought at first the box was our magicbands shipped early by mistake. Everything came really fast this trip before my 30 day mark, and the jump drive was closer to 45 days out. I booked the whole trip right under 60 days.