It's quite fun and a good way to cover up stains that can't be removed from well, nearly all tshirts of her kids.
The cinderella one stayed well adhered whilst being worn all day, but when it came to machine washing, it just peeled right off and didn't make a mess of the shirt at all.
Could be a cool way to change up plain tshirts for special events,
so you can peel it all off after and use the tshirt again.
More info here for you if you want to give this a go.