Did anyone have a problem with this or was it simply the style (Mod fashion) and fashion of the time?

It was the style of the time.

can confirm - I was in High school in the early 70's and skirts were as short as could be - lots of skirt mal-functions ! got to the point that girls would say "It just my underwear" as you may hear on That 70's Show from Eric's sister

It was the style of the type; Most fashionable girls wore miniskirts in the early 70s.