Slack security

I own several pairs of trousers – oh yes, life is going well for me. For the vast majority of these, a single button is considered adequate to bind the left and tight halves of my trews together above the fly. I find this arrangements to be very successful, and in my many years wearing trousers no disaster has ensued as a result of this single fastening.

I also own a few suits and all of these possess three separate fastenings – two buttons and a clip, or two clips and a button – to hold the tops of the trousers together. Why is so much additional security deemed necessary when wearing a suit? Is the typical suit-wearer paranoid about his (or her) trousers descending at an inopportune moment? Surely a belt or a pair of braces (or, indeed, both – or should that be all three? – for the really worried) would deal with any such concern?

Or am I missing something? Should I be looking to add extra security to my less formal leg-wear?