Man, quick to judge...
No, it wasn't 'on top' (as defined anyway).

This is East Tennessee, where we happen to have fog in the ground A LOT.
It was a 'severe clear' day over a coat of low lying clouds 7000+ feet below us.
The 'top' of the clouds was 50-100 feet above the surface, but the 'holes' in the blanket were far and few in between.

And although the terrain is not necessarily mountainous, it is not Kansas either.
The rationale was to keep the glider high enough to allow them to find a hole over a suitable landing site in the case of an emergency.
And I am done posting.