Over the years I've been stopped by Cops for running or Practicing Martial Arts many times.
I once had a cop pull his gun on me beacuse he stopped me at a park after dark, which I'm aware is against the rules, but I was 16 and loved night training and it was only like 9. He stopped me and frisked me, when he got to my ankles (Which had ankle weights straped to them) he jumped back and pulled his weapon. True story. I almost shi* my pants
In hein sight it's a good thing I didn't run cause he probably would have shot me.