If you don't keep it upright at all times, your belongings will fall out.  The sides expand enough that when it's closed there is a gap on both sides that the flap doesn't cover and anything that will fit through those gaps will fall out when you set the bag down.  Asthma inhalers, pens, lipstick, change, hand sanitizer, etc.... plan on playing "chase" with your stuff.

And the metal clasp on the strap broke... the strap is fine, the metal snapped in two.

All in all it's a nice idea -- it just didn't work out well.