If they are not dog people they will not understand the yellow bandana! Protect your dog and advise them "do not approach, she is in training & is not good with strangers". Most people will understand but be prepared to have to be flat out rude and turn and completely change your route. Also think about a training vest with big bold letters training DO NOT PET!!
Police Service Dog Black Vest Harness with 2 Embroidered 'do not Pet' Badges | eBay
Athena- Long Coat GSD -CGC
Sinister Black- GSD