Well, this does cast some useful light on the matter, but frankly I still find this, er, policy almost as incomprehensible as the behaviour of women whose choice of which handbag to take with them takes input not only from the type of occasion but also from what clothes they'll be wearing. They must forever be finding themselves missing some essential item which they left behind in The Wrong Handbag.
I can understand that if your linen shorts only have sewn-in front pockets, that your "cannonball" might be prone to uncomfortable dangling. I always avoid any trousers which don't have two proper back pockets. The trick is to limit the size of your "packet" by having only cards and notes in the actual wallet, and keeping coins elsewhere. The wallet then goes into one back pocket, the change into the other, either loosely or in a dedicated container. You can get fancy leather pouch things for this, with a folding lid, but I just use a bank coin bag - they wear out more quickly but cost nothing to replace.
Perhaps it's just that I'm so afraid that any occasional absentmindedness might result in my wallet or keys being inadvertently left behind in The Wrong Trousers, that I make a point of always transferring everything into the ones I'm wearing. This works so well that I feel almost naked when any of my pockets is empty.