Cellphones and "Do What I Mean"

My cellphone is in the 510 area code. Alice's phone number is 650.555.1242. I have it in my addressbook. When I dial "5551242 send", I mean to call Alice. But I end up calling Bob at 510.555.1242.

What's better: a consistent interface that consistently makes you call the wrong person, or a "do what i mean" interface that is inconsistent but does the right thing 99.99% of the time?

To complicate things further, the phone displays "Calling Alice..." even if I dial Bob's number. So the phonebook look up procedure is "do what I mean", whereas the dialing itself is "consistent".

Any pointers to comparisons of cellphones based on human interface are appreciated.