Fretless Extremity

i was reading through a TIME magazine the otherday in the dentist and i came across a musician section. It had a thing about a new feature on some basses. there was a switch type of thing which let you move the frets in and out, thus, either having a fretless or non-fretless. It souds a little extreme but has anyone else heard of this? i was thinking about it and wouldnt it effect the action of the bass extremely?
anyways mods delete this if there arent ne replies

cya
kirby