Nothing fancy was needed, he wasn't expecting burgundy footwear to match the school uniform at Glenn Hills primary, Leicester, it was just a minor relaxation of the rules.
Minor indeed, but enough to let the imaginings that comprise the fashion sense of small children run wild.
Even when the first pupils arrived in giant animal-shaped fun slippers Mr Wood did not suspect the onslaught that was to ensue. "When it was just a few pupils," said Mr Wood, "we thought it was quite amusing."
But then more and more pupils started to come into school wearing enormous silly slippers - many with huge ears and tails.
Soon an army of bunny rabbits, dogs, cats and monsters was marching into the school each day.
Eventually, the craze became such an outsize one that Mr Wood had to issue an urgent newsletter to parents banning the big slipper.
"Although these slippers look great, they are actually dangerous," said the newsletter. "Pupils have tripped over their own slippers as well as the ears, tails and floppy bits of other children's slippers."
And his actions have been backed by the Royal Society for the Prevention of Accidents. A spokesman said: "These sort of slippers are not built for moving in a hurry. If the school had to be evacuated in a fire emergency you could have children falling over each other all over the place. It was a sensible decision to ban them."
But didn't Mr Wood have the slightest yearning to succumb to the craze as it swept through the school? "What I get up to in the privacy of my own home is up to me," he said. Mr Wood does not own a pair of tiger feet.