Chewtobacca said:
Size: 15.7 GB (16,888,247,344 bytes)
Size on disk: 15.7 GB (16,888,250,368 bytes)
Those GBs are actually GiB. If the file in question is 16 888 247 344 bytes, it is 16.888247344 GB (gigabytes).
1 GiB (gibibyte) = 1 073 741 824 bytes
1 GB (gigabyte) = 1 000 000 000 bytes
The terms are often used interchangably, thus spawning some confusion. Drive makers use GB, while operating systems usually use GiB, while still calling it "GB". If the USB stick in question is marketed as 16 GB, it probably has room for 16 billion bytes, thus making to file too large. He'd have to remove some audio tracks.
Also, since I'm posting here anyway, I might as well use this opportunity to say thank you so much, Harmy, and happy birthday.