Only children's outerwear hoods and waistbands fall under the drawstring regulations. Although, the government regulations do not cover sashes, ties and straps, some retailers in their regulations to the vendors that make children's garments have very strict lengths. For example, sash tie ends may not hang lower that the hem untied. So always consider the reality of kids doing things possibly unsafe and unexpected and take that into consideration when designing . I'd modify the design so that the strap can't be pulled out.
