The blue background isn't lock-in -- it's branding and fashion. It's labeling the in-group and the out-group. The cool kids with their Nike shoes and the kids who got their shoes from Payless Shoe Store. The Abercrombie & Fitch wearing kids vs Costco or Walmart wearing kids.
The sooner it can be learned that a symbol on a shoe is ... kind of a silly status symbol, the better. Same with blue background or blue check mark.