Jim says
"I've been on the folk scene since 1963, not full time admittedly but have NEVER seen a drumkit in any club or session "

I've seen that at The Keith Festival sometimes. As well as the traditional singers and musicians, the festival usually books one or more dance bands. The Fiddle and Accordion scene is very strong up there. So, you'll often get them bringing parts of their drumkits into the pub and sometimes keyboards etc too.
Sometimes, everyone can mix in Ok, sometimes not.

The discussion about Jimmy Shand is quite interesting. Although he is known for his "strict tempo", Jimmy has always had appeal beyond the strict SCD scene. His early music was more "traditional Scottish/Irish" than just "Scottish Dance" and he was also played melodeon, of course.

Many of the folky/ceilidh tunes and SCD tunes are interchangeable or can be. It's just the playing style which differs.
Whatever takes you fancy, at the end of the day.