The screws on mine remained tight even after they let the sight base slip. I got lucky, it caused a clean miss. Twice. I did what any normal person would do, I checked everything the first time including the screws. I resighted it, wrung it out good, and wrote the miss off to the cheap scope. The second time it happened I had already changed out the original scope to a Zeiss Duralyt so I began going through the mounting and found that even with the screws tight the base could move. I have heard they changed the base attachment design to fix it but I have never seen that. In my case the base moved enough to cause a clean miss. Twice. I got lucky. If it can move that much it can move less and cause the problems that come with a bad hit. Mine never moved left to right, just up and down, and the vertical movement was only barely perceptible. It's a bad design, I'd check if those are pan head screws and do the mod if so. Keep an eye on it, if they are pan heads it will slip at some point.
