Just have this in demo mode.

But.. when Account registration. You dont get send directly to verify phone number you need to push on something in account to verify this.
Not possible to verify directly?

If my number is 888 777 222. And someone use this but cant verify it... what will happend when i try to register be myself?

you should not be able to register with phone other user is using.

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?

@Rick
Same can happen with mail.

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?

That's not a good idea as it could open up the plugin for abuse. Best to notify user of already registered number and to contact admin/support for help.