Countersunk screws - NOT for frameless panes!

I've mentioned this in other posts, but as a customer kindly provided an image of his OOD34 frameless window, I think this demonstrates why using countersunk fasteners in acrylic frameless panels is never a good thing.

You can see how the acrylic is cracking around the fastener holes here. If the fasteners were pan-head and the holes slightly oversized for the shank diameter none of these cracks would have developed.... Just saying...