I did try this..
Reg a acc with 727171711.
But NOT verify it...
And try now with same number with another new acc...
Phone number 727171711 is already registered to another account, please use different number
This open up for pepole to spam with other numbers so they cant register. It dont need to me the owner that have taken it.
It would be better it send code but it will not be "already registered" if not it have been verifed?