On the Unibody portables, the trackpad is not soldered in as with the preceding machines, but dismountable. However, Apple did not provide this part by itself for after-sales service so one is obliged to replace the whole case of the machine in the event of failure. At the beginning of June, it will be possible to make exchange this part alone.
Even though this has a small impact on the affected customers up to now, since repairs were done under guarantee, they will in future be able to replace a failed trackpad at a cost much lower than that of the whole case, especially as the time to do the repair will be much less.
Of course, Apple will also make large economies for the exchanges under guarantee. One asks why they have taken so long to propose this!