Running Fans and Feet = shortened stature

It made perfect sense for my sons to run their fans on summer nights. After all, their bedrooms are upstairs, and heat rises.
The whirring fans also brought back memories of when I was a girl sharing a double bed with my two little sisters in muggy New Jersey. We always ran the fan on hot nights, where the humming blades and gentle, artificial breeze were like a lullaby.
Who knew it could be dangerous? I never suspected, until my big 14-year-old Brian came limping down the stairs a few weeks ago. "What's wrong?" I asked.
"Well," he said, sinking into a chair. "I woke up in the night because my foot hurt. When I flipped on my lamp, I saw that somehow I'd stuck my foot out of bed and caught it in the fan." He indicated a huge blood blister under his big toenail, which is part of his size 14 feet, which are stuck onto his 6' 3" body.
Bad Mother Moment: I'd let my older son use the fan with the broken safety cover, so his younger brother could have the fan with covered blades. I never thought of my tall son's legs being long enough to stretch out of bed far enough to be shortened by half a dozen spinning plastic blades.
I marched right up the stairs and took the faulty fan from my son's room. I gave him a safety covered fan, and encouraged him to set it on his desk. But then... his desk is beside his bed. You don't think his fingers are small enough to fit through the safety cover slots, do you?