In my neck of the woods SHB are everywhere these days. I've always used telescoping/inner covers ever since I've started keeping bees. With the advent of SHB, every time I remove the telescoping cover, I see SHB on inner cover. I think it just gives them a place to hide from the bees. I've changed some of my tops to migratory covers over the last year and this year will change out all my covers to migratory covers in an effort to keep the SHB at bay.
I'm only new to beekeeping, but this is exactly my experience.