They have a slit but not as far down the side. Hot glue has been tried with horrible results for accuracy but that isn't the point of them. At close range they are shotgun bombs. Silly putty has been tried too but I never saw any drastic results, it just was a goofy looking shell.
Good intentions will always be pleaded for any assumption of power. The Constitution was made to guard the people against the dangers of good intentions. There are men in all ages who mean to govern will, but they mean to govern. They promise to be good masters, but they mean to be masters.