It is probable that most of the MK IV computers are running older software. The BMW dealer instructions for the software update disc say "only upgrade in the event of a customer complaint". It isn't something that's done as part of a scheduled service visit, either.

So, you'd get people bringing in their cars saying that the navigation isn't working. Best case, people would be paying $100+ in out-of-pocket labor expense for the update (I've never found a dealer that would charge less than 1 hour for a paid service visit, though a number of dealers will "freebie" stuff like light bulb changes, NAV software updates - for MK IV cars only, updating the CCC version takes hours). Worst case, a few customers will be told that their NAV computer is broken and they need a new one. Either by a dealer who didn't hear about maps requiring V32, or by an unscrupulous dealer.

Once TeleAtlas settles in as the regular BMW map provider, maybe they'll include a coupon for a software update at the dealer or even supply the V32 update as part of the map package - it's only $10 or so from the dealer, anyway. But that will probably depend on how much feedback they get from customers who don't want to swap map discs back and forth.