My HK VP9-OR and OR-Los have a very robust mounting system, and I use correct procedures for installation.
Since July, I ran an SRO through two separate classes with Larry Mudgett, a range day at Gunsite, the Gunsite Alumni Shoot, about 20 trips to the range, and a week long 499 class, where the optic took a beating (lots of one handed manipulations and malfunction clearances, racking off holster using the optic, etc) and I have had zero problems of any kind with this setup at a round count of about 5500.
Lots of holster wear on the pistol, but the optic is completely pristine. Zero is completely unchanged. I may pull the mounting screws and replace with a fresh set sometime before the end of the year, as the HK maintenance schedule for the (rather beefy) plate screws which secure the plate to the slide have a 2000 round maintenance cycle. Or, I may just keep shooting and checking as I go.
I won’t go out of my way to abuse the thing, but a proper mount and reasonably robust optic is actually a potential asset to pistol manipulations in my experience.
<--- left-hander.
Initially, I was swiping at, chopping at the optic.
Now, with a handful of administrative manipulations, I may well grab the forward portion of the slide. However, for clearing a stoppage, speed (slide lock) reload, and the like I grab the whole optic in an overhand grip like I would the rear of a bare slide. Aimpoint Acro, RMRs, Leupold, and Bushnell's new offering.
@GJM's mention of unintentionally adjusting the brightness setting is interesting. I'll try to keep that in mind and see if I encounter that going forward.
I’ve been working on re-training myself to work the slide utilizing the front serrations. Occasionally I’ll go dumb and revert to trying to work it from the rear (phrasing).
“Conspiracy theories are just spoiler alerts these days.”
The only thing I don’t a thumb over (towards the ejection side) the top on the front serrations manipulation is when there is a serious jam that locks the gun up and needs real force to un-jam it. Then it’s a full grip over the top (fingers toward the ejection side) and use my firing hand to hit/push the frame forward. The thump over at the front serration manipulation is much more efficient if you care about economy of motion.