I’ve had this happen to me. I’m pretty happy to talk to anyone who approaches me so I made the mistake of saying hello to a girl who said hi to me. Being on Khaosan Road I should have known better. Anyway, she kept following me and asking me to engage in various acts for money, or even for “free”. I kept saying no thank you, I’m good, but she kept following. I had to form a brisk jog to get away.