I do a lot of borderless quilts. Depending on how many seams are along the edges, and how much the quilt's been handled, sometimes I'll do a quick basting-type stitch all the way around to stabilize the seams. But if they're all holding together nice & tight, or there aren't many seams per edge, I don't bother.
I don't have a serger, I just use my regular machine with a long stitch length, mostly because I'm impatient and want the step to go quickly, and those seams only need to hold until the binding is in place.