If you want to know where you said that error checking was useless, that was post #40. Although to be honest, I'm not sure anymore what point you're making.
The idea is that the input format, as given in the original post, is " %c %c %d". You can use a different format if you want, but then you are going to be matching a different format than you are supposed to be using, so either you will (1) fail to match proper input or (2) improperly match incorrect input or (3) both, depending on how you muck it up. In this case leaving out the second space will cause (2) to happen, and CT conveniently posted an improper input file that your code will claim is accurate. [It will eventually fail on the next line, so not too damage is done, but.]
EDIT EDIT EDIT: And you know, by now, you'd think I'd remember how spaces in format strings actually work, but I didn't: a space in a format string can match no spaces in the input, so the original code would fail in the same way. So all of this fuss for nothing! My apologies. (We'd have to read a line with fgets or similar and check there's nothing left over to actually check.)