I say always be open minded about stuff like this, IMO. Personally, I think this is much less extreme than having a hair transplant...
It's being promoted here in the UK by a Celebatory hairdresser. Some actually look quite good, others look like someone has coloured their head in with a magic marker!I agree about the getting older thing, will look really odd on a 60 70 year old. And it is not as if they can have it wiped off and start again (unless it IS a magic marker!)