Thanks. Is foam over foil a mechanical switch?
There's no true definition of "mechanical switch" that everyone adheres to. Some people consider everything that's not rubber dome mechanical, others don't even consider the Model M mechanical.
In the truest sense of the word, "capacitive" would probably be a more appropriate than "mechanical", but then again, I can't really think of a switch to which the term "mechanical" would apply best.
My own advice; I'd call them mechanical, but stay away from foam-and-foil boards. The foam will almost certainly have rotten away, leading to highly unpleasant switches.