I am an IT professional who has come to the US for medical treatment on a B2. I am getting better. Since I like to constantly upgrade my skills, I found some training programs that I could attend as they are more frequent in the US than in Canada. Can I attend them on a B2? I mean I have a B1/B2 visa, but the officer marked it as B2 on the stamp on my passport at the POE. Second - I also have got an offer for a one day lecture to some technology professionals for which I might get paid. How would the folks know I worked for a day if while exiting the country there is no checking?
I believe you can take training on B-2 as long as your main purpose of stay in USA is is still medical treatment. Getting paid may be a bad idea.