for the attached test-case, hunspell seems to ignore the lines after \EndSomething until the \end, when started in tex-mode.
% hunspell -d en_US -t -G test.tex
Note the missing 'Yes'
% hunspell -d en_US -t -L test.tex
Note the missing 'Hurz!'
It seems, like every latexcommand, that starts with \End makes hunspell ignore large portions of the text.
(And I have the impression, that there are even more parsing bugs, but this is one I could nail down.)
Btw: hunspell-1.3.2 used here.