No, mine hasn't pancaked onto the windscreen, but I think I might have just prevented it in time!
Yesterday evening I noticed that the bonnet was sitting a mm or two high, and wobbled when closed (but the catch seemed to be working properly). Further investigation this morning found that the pin which drops into the striker plate (and the catch engages with) had worked loose. It's screwed into the bonnet mounting plate with a locknut to allow for adjustment, and a few turns of shiny steel were visible. As I have never touched this (and the screwdriver notch on the end was full of mud, so it evidently hadn't been disturbed intentionally) I can only assume that it caught some WD40 at some point and then slowly worked loose from vibration. If it had carried on turning then presumably it would have unscrewed from the bonnet and allowed it to flip up at speed.
Problem now fixed by screwing it back in and tightening the locknut. I'm wondering if this may have caused a few of the bonnet catch failures I've heard mentioned. I don't want to fit bonnet pins as the standard mechanism has been fine for 14 years and I see no reason for it to prove weak, if properly adjusted and lubricated.