That’s why japanese people sometimes when introducing themselves also mention the kanjis because of the wildly different readings. There is literally no way knowing the reading if the user doesn’t provide it.
I don't know if this is really true, but I've been told it's really so that you don't forget people's names when you first meet them. In Japanese, it is impolite to use the second person pronoun ("you") with people you don't know. So if you forget their name, it can get pretty awkward if you want to talk about them. When you receive business card, you are suppose to inspect it with great attention and it is common to hold it in your hand or put it on the table in front of you while the person is there. Whether that really is an aide to help you remember names, it certainly does help! It's the thing about Japanese culture that I'm the worst at (and to add insult to injury, I've yet to print any business cards after 10 years here -- it's so embarrassing when I meet people :-P ).
