I agree with you, however there are some companies who block outgoing callers name, mine is one and so is a lot of aerospace companies.
But does it also mask your phone number?
The OP's issue isn't so much with :
UNKNOWN NAME
1-555-867-5309
as with:
UNKNOWN CALLER
(No Number)
The latter is known as a "blocked (CID) call" and is what I had blocked on my landlines, like the OP is talking about (Anyone who had CID block their phone number received the message "The person you are calling does not accept blocked calls. Please hang up, dial *82 and then the number to try again" - *82 being the command to unblock one's number for that call only.
4.0.2 does indeed patch the exploit used by jailbreakme.com to jailbreak your iPhone - this is the most recent update. One of the first steps in fixing one's phone if something goes wrong is to "Restore to Factory Settings" which undoes jailbreaking, but yes, they can deny warranty claims if your phone is jailbroken - but we also have plenty of users who've JB'd and received warranty work anyway.Doesn't jailbreaking void ones warranty? And didn't Apple just release an update which blocks "jailbreakme.com" from working?
You'd probably get more results posting a feature request here.
Or to you service carrier directly.