I thought I would share something I have done to a few of my jackets. Some of them have inside pockets, but with no velcro/zipper etc., so I have sewn buttons on for a bit of security. At least this way things won't fall out.
I just did this again to my Fjallraven that I am taking with me to the Christmas Markets in a week. It does have a zippered inside pocket, but also two large sort of open pockets. I made loops out of cordless paracode and sewed those on and then buttons of course. It looks quite nice, and I know it works since I have done this to other jackets.