A. Brake suddenly so you don't leave the road
A. Brake suddenly so you don't leave the road
B. Look through the gap underneath the bonnet or out of the side window
C. Signal, brake smoothly, and pull to the side of the road, then refasten the bonnet
D. Turn on your headlights and look out of the side window
It's extremely unlikely that your bonnet latch or catch will fail. Almost all bonnet catches have a two-stage release so that if the first stage fails it catches on the second stage.
However, it's not unheard of as you can see in this video which shows just how much damage it can do to your bonnet and windscreen at 60mph (100kph)
If you have some existing damage to your bonnet or the front end of your car from a crash then it is more likely that your bonnet catch will fail. It could be that the bonnet won't secure in place, or the catch won't clip all the way in. In this case, heavy buffeting by wind on the bonnet can flex it enough that it pops the catch open.
Another reason is if the bonnet catch or the surrounding metal has rusted and therefore become weak. Driving into a headwind will increase the load on the bonnet catch and might cause failure.
Or, it might be that you (or someone else who accessed your engine bay), didn't secure the bonnet catch firmly.