Quote "What is wrong with running a strictly traditional club?"
The problem is "Who decides what is traditional?"

1. Most of our songs "as collected" are not. They are often imperfect recollections of printed songs, often with known composers.

2. Most of our instruments are not.
You have to remove all free-reed instruments (Accordion, harmonica, concertina), invented since 1830. Guitar is not traditional either, at least in British folk singing. Maybe harp, whistle and fiddle would be acceptable.

3. Harmony is not traditional either, with a few exceptions.

4. As note above, most of the singers of "traditional" material have altered or replaced tunes.

Doesn't leave much, does it?