Looks like DigitalOcean has just begun measuring bandwidth usage "officially", starting yesterday:
https://www.digitalocean.com/community/tutorials/digitalocean-bandwidth-bill...
"Based on our analysis of the historical usage patterns of our customers, less than one percent of users will exceed their pooled allowance."
I had heard of the One Percent, but never thought I'd become a part of that illustrious group... :-)
-Ralph