Anyone that phones you and won't identify themselves is very strange. They are either being silly and playing head games or harassing you. You didn't say if this was a good or bad thing. If you don't have 'call display' where it will give you a phone number or name or both, then get one. If you are being harassed by someone then phone the operator as soon as you hang up and explain your problem and sometimes they will trace the call for you. If you just get a number then go onto Google.com and type in '411 information' (that's Canada) so put the American information number in. You can put the phone number in and it will give you the name unless it's a private number.
If there is a reasonable suspicion that someone or something is in danger, then yes.
*67
by a letter or email or Skye
Well u could send mail or a email
you ask them to forward it to you. or you secretly grab their phone then forward it to yours, then erase when the message in the sent box.
Yes. How dare can he/she
No, that would be illegal.
find a reason to ask them how they spell their name
yes and it would be easier if you use bluetooth
In order to block your phone number when dialing out, you must first press *67, and then dial the number. This allows you to call someone without your phone number being available to the person you are calling.
Without permission it is illegal but if they ask you to then it's legal because you have their consent.
If you borrow someone's phone without their permission, even if you intend on returning it, you've committed "deprivation of property". If the individual allows you to borrow the phone, or you know they will not care, then no crime has been committed.