I've had a few online surveys from BA in the past where they haven't indicated which flight or product that they'd like me to comment on. For example after a BA Holidays trip which contained stays at 2 different hotels, they asked me for feedback on the stay. The problem was I couldn't give an accurate response because the survey didn't give a reference number known to me. It has happened after multi-sector flights as well. I don't mind giving feedback, but I need to know exactly what I'm to comment on!