Why? Because that's not the point of liturgy.
Now, maybe some of the people who approached me do not understand the purpose of liturgy and saw it merely as artistic expression. Maybe some have a fuller understanding of liturgy but don't possess the language, or are not comfortable with the language necessary to express their gratitude "appropriately". (It was even used by a musician from another parish.)
Or maybe I've just got my head stuck up my own backside!

But it's really got me thinking!