Folklore Quine: did you ask BEFORE starting to record whether it was OK to do so, and/or state for what purpose you wanted to record? In this day and age of smartphones and other digital recorders, there are perhaps too many of them waving around recording either video or audio and distracting other concert/session-goers.
Having been an organiser at other singers' events (as well as an attender at Cullerlie and various instrumental workshops), we would ALWAYS ask any of our guest artistes for their ground rules about recording BEFORE any sessions or workshops started, and communicate the artistes' preferences to participants. Most, with few exceptions, would say it was fine for personal learning use only, but absolutely NOT to be broadcast on any social media such as Facebook or YouTube, and this was taken on trust. This should apply whether or not the whole procedure was being recorded.