I've run BC flips on all my scopes-never a prob. Occasionally, when riding over my shoulder against my pack the front might flip open but it aint the cover's fault. And, yeah, +1 to the poster who said they (BC) are way faster than a bikini when operated correctly. The only thing I want a bikini on is my woman--and even then I prefer it off!
The Leupy screw in Aluminas ARE really nice but too expensive. I got some in a great deal on my fixed 3x from a member here.
Chris