...probably have only the one tune in them anyway...

That's fine for beginners.

There's still nothing wrong with encouraging them though. First it's just to get them up on the floor, then you introduce them to new stuff.

But as breezy says - after 30 years!!! I should be pointed out to them that there's about 9000 songs here on DT.

It can be done nicely - "Hey have you seen THIS WEBSITE - lots of good new stuff there".

The Bucks County Folk Song Society in PA have a different theme every month. It's great, if you can't find a folk song that fits then they are delighted with any song especially if you have to write one for the occasion.