so if you leave
the glider for some time, you close the canopy and cover it.

In the cockpit fire that I know about, the soft cotton canopy cover was placed
over the instrument panels to keep them cool and the canopies were left open.
Not a good idea to leave any combustable material on the instrument panel, not
even your hat. Close the canopy and put the cover on is the best rule.
JJ Sinclair