I had a scammer who was a highly rated buyer. I did the work that she'd touted me for and not something I offer a gig for and then she cancelled. On another occasion I had a buyer who would not give me the information I needed to help her. I had to get time extensions and finally go to Fiverr support and mutually cancel. I was told that it would not impact my algorithms because they'd helped me and supported me. But now orders have dried up which is weird.
I'd love to be able to only take orders from clients who contact first. Despite my opening example, It's frequently those that are placed without contact that prove problematic.