And I thought I was the only one. Some years ago I used to play in a pub every Sunday night as an offshoot of our folkclub. The last straw was when I saw my precious Yamaha FG300 being handed over to someone whilst I was at the bar without a thought of asking if it was okay. I moaned so much that the club organiser nearly went out and got a spare club guitar for 'those without' to play.
Since that time I have various guitars. Most I do not take out unless I am playing a personal gig. ( And I make it known that I do not 'borrow' these guitars. My old battered Yamaha FG 401 gets taken out to the pub sessions and whilst it has become personal to me I don't mind it being played by someone who has turned up on the night by chance.
I like the DADGAD idea but I have seen so many strangers try to play an out of tune guitar during the course of an evenings drinking that it probably would not make much difference.
I suppose the polite 'no' is best - then wait and see.