Far too much things to remember:
Carefully peel animated decal from front of T-Shirt
Unplug ribbon connector behind decal and remove decal
Unplug battery pack and remove it
You can leave the ribbon cable inside the shirt
Machine wash gentle cycle on cold
Hang to dry
What happens when your wife forgets to remove all of that? Hell, who would want to do that themselves? Off and on every single time you washed it?
Also, don't ever go to a theme park with that on, and ride a water-themed attraction.
Watch the weather in the morning. If it's not raining in the morning, and it will later, don't be caught off guard so that you can take a jacket/coat.
Too much trouble in my opinion for anything other than hanging on a wall or something. I believe this to be one of those ideas that looked absolutely sweet on paper, but no one had half a brain to think of the negatives.