I have one of those pincushions, too.
When he last visited, my 13 year old nephew exclaimed, "Aunt Cathy, you have so many pins on the floor!" Which was code for "why don't you pick them up?"
I told him that's why I wear shoes all the time. In fact, kids that normally go barefoot in the house know that shoes are required when visiting. They have learned that lesson from finding pins with their feet. Maybe that's why they leave lego's on the floor...to teach me a lesson.