Holy shit people. Slow the fuck down. You're all assuming that this is for some sort of evil data mining conspiracy. It almost certainly isn't. They are almost certainly asking the kids to provide their own elastic strap for the heart monitor, the thing that tell them and most gym-quality cardio equipment how fast their heart is beating. The sensor and watches (if they use the watches) are plastic and cleanable whereas the elastic strap isn't (short of a wash cycle in a washing machine). They just want the kids to bring their own strap so that they are only wiping germs and dried sweat onto their body that came from their body anyways (ie, not sharing that which carries carries germs). This isn't a big deal. Did you flip out when your kids were in elementary school and the teacher told you as a parent that your kid had to bring their own comb or brush to school instead of sharing with everyone else? It's not the big deal that everyone is making it out to be.