Malc, the full stop thing is just ludicrous---particularly as they asked you to re-submit it in the "corrected" form. I'm guessing someone was having a bad day.
I guess there are two ways of looking at this. It does seem more than a little pedantic, and officious, but it also shows that our cartoons are being very carefully checked, and that can certainly benefit us as contributers from time to time, especially if there is a glaring error in our work that we fail to notice (it happens).
I agree that this 'error' appears to be insignificant, but I think on balance, I'd rather know that Cartoonstock are paying close attention to such details, than allowing any cartoon to pass through their gates unchecked. I also
know there are many pedants among the 'cartoonist community' who would probably be eternally grateful that even an AWOL full stop was spotted and prevented from entering, and who would have been apoplectic with embarrassment had it not been (they know who they are... koff-koff!).
Unfortunately, these things can't be corrected by Cartoonstock themselves, since text is part of the artwork, and only the can or should be allowed to change it, and so it had to be returned for the change to be made. They could have let it go, but on balance, I'm happy to hear they didn't.
Sorry to the majority of you out there who haven't a clue what any of this is about, or care even less.