Locals paying for their tickets for a show at the *village hall*, may well not be familiar with accepted norms at a *folk club*.
The lady who complained would no doubt be similarly annoyed by someone next to her speaking along with the words to the local Am-Dram production of "The Importance of Being Earnest" or singing along to the local Operatic Societies production of "My Fair Lady", or similar stuff. Panto excepted of course. I think when in doubt concerning what it's aproppriate or not to do in any social or group circumstance, taking note of the unspoken consensus of behaviour, has got to be the most useful guideline. When in Rome and all that.