Re the purpose of visit, have the rules of what is defined as work changed recently? I traveled a couple of years ago to LA to work on-site with my employer for

Re the purpose of visit, have the rules of what is defined as work changed recently? I traveled a couple of years ago to LA to work on-site with my employer for a couple of weeks - I told the customs official this, and they let me through without issue. I'm from the UK so just got ESTA.