For someone who is handicapped, or paraplegic, or who broke one or both hands, zippers might be difficult. Enter the electro-magnetic zipper.
When no current is passed, the two halves attract and keep the fly closed.
When it is time to do your business, you press a button hidden somewhere, not
easily accidentally pressed. Maybe in your shoe, or attached to your waist so you can press it with your elbow. A current is applied, and the zipper halves repel, or at least stop attracting.
A timer could be added to only add the current for a certain amount of time (30 seconds). Each button press would extend that time. Press and hold for 3 seconds to leave the current on until the button is pressed again.
Not much current is needed.
Could also be applied to other pieces of clothing: hospital gowns (no more butt hanging out), jackets, belts.