It does happen. A few months ago I checked in to DT on a Sunday (of all days) to find I'd had 54 downloads. I was a bit sceptical at first but the sales remained. The OP didn't say if the images he sold were connected in some way but in my case they were all of my late 1970s rock/pop bands (Thin Lizzy etc) so likely a buyer with a particular project. I've had the same thing happen several times before on Shutterstock with the same images. Congratulations Kenny!