I recently noticed this on Fiverr.com. I had used it in the past and wasn't ever hit up for a tip. Paid for some work to create some icons just the other day,

I recently noticed this on Fiverr.com. I had used it in the past and wasn't ever hit up for a tip. Paid for some work to create some icons just the other day, and the payment flow hits you up for a tip at the end. With wording like "It's customary". And a minimum tip of $5, regardless of the order total, though you can opt out altogether.