The most SD corruptions I got on my devices like mobile phone,
gps, etc etc is condition of totally fcked - "do you want to format blabla" after inserting to card reader.
In such condition nothing is available to device - no risk of launcher.dat.
If your SD card will got corrupted - then launcher.dat will not get 'launched'.
To get launcher.dat running it has to be in working condition,
in order to execute checksum code.
If the file is corrupted, then it should not execute,
should not make checksum, and should not brick.
Just try on your own to "corrupt"/modify/cut some peace of exe file on pc - will it run?
My another two cents