Wearable location tracker for toddler?

My son (2.5 years) is with my parents every day. Now that he's a bit bigger, my dad sometimes takes him on adventures to the city (train ride, walk around, come home) or on walks around the neighborhood with my dad or my mom.

They are both capable caregivers and we don't worry about him separating from them by running off but we do sometimes worry if one of my parents had a medical event (or one of us for that matter) that he could be on his own in an unfamiliar place and not able to communicate effectively. Our worry is compounded by the fact that we don't always know where they are planning to go for the day.

Does anyone have any suggestions for an affordable smartwatch or bracelet or something he could wear during the day that would allow us to see where he is and for someone to get in touch with us in the event of an emergency? Or are we being too crazy to consider this at this age? Would just an emergency contact bracelet make more sense?