I did try removing it, and it failed somewhere further downstream. I'll have to poke some more
Here's a hex dump of the beginning of my card (formatted by a camera) The string is there, but probably in a different place...
00000000 eb 3e 90 50 77 72 53 68 6f 74 20 00 02 20 01 00 |.>.PwrShot .. ..|
00000010 02 00 02 00 00 f8 ec 00 3f 00 20 00 87 00 00 00 |........?. .....|
00000020 79 73 1d 00 80 00 29 ca 21 c5 50 43 41 4e 4f 4e |ys....).!.PCANON|
00000030 5f 44 43 20 20 20 46 41 54 31 36 20 20 20 33 ff |DC FAT16 3.|
00000040 8e df be 00 7c 8d 9c e4 01 8e 47 02 fc b9 00 02 |....|.....G.....|
00000050 f3 a4 c7 07 58 00 ff 2f 8c c8 fa 8e d0 bc 00 06 |....X../........|
00000060 fb 8b ec 83 ec 16 c5 36 78 00 89 76 f6 8c 5e f8 |.......6x..v..^.|
00000070 8d 7e ea b9 0b 00 57 f3 a4 5f 8e d9 be 78 00 89 |.~....W.....x..|