problem with having your nametape on your shirt is that as soon as you put a chest rig or plate carrier on the tape is obscured, makes more sense to have it velcro backed so you can just stick it on to whatever load carrying equipment you're wearing, or the back of a helmet, or a sleeve pocket... you get the idea! Lots of people have various different kit for playing in different places or at different times of year, with the name tapes and patches velcro backed you can move them between kit easily, sewing them on to everything would take hours and cost a fortune in name tapes!