Well I would think most people wouldn't be comfortable with any company having record of their kids locations all day, every day for years [1]. Why would any sane parent want to give away this data to a startup?

Parents who buy this app are crazy(imo).

[1]sure your cell phone service provide has this data but (a) that can't be helped (b) location tracking isn't their business and (c) they don't specifically target kids).